iM 4,1-14,4 2011 iMac Graphics Card Upgrade

[Surf2bikes]

Try flipping the shim upside-down. (Those shims are slightly bent due to press-cutting, and the way you positioned it will leave a small gap between the shim and the heatsink.) Even better - use fine grit sandpaper attached to a solid, even, hard surface to 'polish' it first, clean it with isopropyl alcohol, and mount it again. Since you repositioned the ODD temp. sensor, you can use it without MacsFanControl. (At least that's how I use it...)

Take a visit at my special installation post of the WX4130.

My temps are only a few C different and the fan always works properly.

You experience over heating shutdowns.

Thank you guys. I will definitely re-vesit my mount and will check and improve as you recommend it!

 

[internetzel]

Yes - I did it like described in post #1 using a 15x 15 x 1 copper shim. I used K4-Pro thermal paste under and above shim. I used K5-Pro vor the VRAMS.

I will re-visit it. Maybe I missed something. I also connected the ODD sensor close to GPU on heatsink. see pictures and temperatures of Mac-Fan-Control (under load using Unigine Valley with UTLRA setting)

K4-Pro performed quite bad when I tried it.
I wonder whether there's actually a thicker shim or grinding needed when mounting an MXM-A card to an MXM-B heatsink.

 

[Surf2bikes]

K4-Pro performed quite bad when I tried it.
I wonder whether there's actually a thicker shim or grinding needed when mounting an MXM-A card to an MXM-B heatsink.

I have also residual MX-5 thermal paste from my previous project. I may use this one instead. Also ...looking at the pictures my shim looks thiner than the one on @Ausdauersportler 's foto. I did not measure the thickness...I trusted the order specification which stated 1 mm thickness. I need to check it definitely.

 

[Ausdauersportler]

I have also residual MX-5 thermal paste from my previous project. I may use this one instead. Also ...looking at the pictures my shim looks thiner than the one on @Ausdauersportler 's foto. I did not measure the thickness...I trusted the order specification which stated 1 mm thickness. I need to check it definitely.

1mm is enough (actually the max needed AFAIK), got a little collection with 50 pieces in different thickness, minimum thickness depends on the sink.

Here I am using MX-2 all the time. You have surely messed the installation completely. Press the springs of the four screws down when fixing the bracket but avoid bending of the card (which is theoretically impossible since the springs compensate the thickness of the GPU and so the distance of the PCB and sink).

 

[vmbl]

Great work!
I've got to add that it's no longer necessary to do the bootrom firmware mod, if you can live without graphics acceleration in Windows. I found a (yet unpublished) way to add those two EFI modules to the VBIOS itself.
In case there's actual interest in such VBIOSes for the Polaris GPUs (Baffin and Ellesmere) I can publish them.

Hi,

I was planning to flash my iMac firmware to install a WX7100 but I saw that you could integrate the modules in the GPU VBIOS
I would be very interested because I also have 2 other iMacs on which I plan to use AMD cards (WX4130/50), with external screen for boot-screen, that would avoid me to flash their firmware and I don't need Windows (from what I understood, no graphics acceleration under Windows) Thank you

 

[HelloDarknes]

Hi,

I have an Imac 2011 at home with Quadro K2000m in it.

Is there any option to flash quadro ROM without taking the whole computer apart?

Best regards.

 

[davidg5678]

Hi,

I was planning to flash my iMac firmware to install a WX7100 but I saw that you could integrate the modules in the GPU VBIOS
I would be very interested because I also have 2 other iMacs on which I plan to use AMD cards (WX4130/50), with external screen for boot-screen, that would avoid me to flash their firmware and I don't need Windows (from what I understood, no graphics acceleration under Windows) Thank you

Usually, people flash the VBIOS chip on the GPU itself, rather than flashing the iMac's motherboard firmware (which is rarely done, more difficult, and usually unnecessary, except for some very rare cases). This means that a single flashed GPU would (theoretically) be compatible with several iMacs, with some caveats. As long as each iMac's boot drive has a properly configured installation of OpenCore Legacy Patcher, and the iMacs are all GPU-compatible from a hardware standpoint, the same GPU should function in several computers.

Flashing the GPU's VBIOS ROM chip is required for many GPUs to even turn the internal screen on. It's not really necessary for most people to have a native boot screen because once you set up OpenCore Legacy Patcher on your boot drive, it will provide an emulated boot screen within a few seconds of startup anyway. The OpenCore boot selector functions much the same as the native one does, and it even works on the internal display. You'll likely need to install OpenCore Legacy Patcher for your display to turn on (and to upgrade macOS beyond High Sierra) if you use a WX7100.

Windows will have native graphics acceleration, as it can use pre-existing Windows GPU drivers, although flashing the GPU VBIOS and using OpenCore Legacy Patcher are still recommended, even for a Windows-only machine. Mac OS typically has more problems with graphics acceleration, but the WX7100 is a modern, AMD/Metal, macOS-supported GPU, so it will have full graphics acceleration.

 

[davidg5678]

Hi,

I have an Imac 2011 at home with Quadro K2000m in it.

Is there any option to flash quadro ROM without taking the whole computer apart?

Best regards.

Yes, there is. See the first post on this thread, and take a look at the section under Questions and Answers, Q3. Flashing the VBIOS can be accomplished (completely in software) through a custom version of Linux (linked under that section) that runs from a flash drive.

 

[JohnPascololo]

I experienced crashing („Driver timeout“) on windows with demanding games with the WX4170 and was able to solve it by flashing the WX4150 Bios. Card runs stable now. Temperature was not an issue with max temp at 66 degree Celsius. Of cause the lower clock comes with the cost of loosing some fps.

As I understand it, the difference between the BIOSes is a lower base clock. Is there a tool where I can easily set the clock speed of the Bios and try something in between, to find the maximum clock speed providing stable operation? Emphasis on easy boys!

Still amazed what you can do with a PC from 2011! It even runs Windows 11 totally snappy and the little one is playing GTA V and PUBG on it.

Windows 10 was having startup problems which caused it to hang on the boot logo and requiring repair every other boot which was annoying and seems to be fixed with Win11.

 

[internetzel]

Hi,

I was planning to flash my iMac firmware to install a WX7100 but I saw that you could integrate the modules in the GPU VBIOS
I would be very interested because I also have 2 other iMacs on which I plan to use AMD cards (WX4130/50), with external screen for boot-screen, that would avoid me to flash their firmware and I don't need Windows (from what I understood, no graphics acceleration under Windows) Thank you

Usually, people flash the VBIOS chip on the GPU itself, rather than flashing the iMac's motherboard firmware (which is rarely done, more difficult, and usually unnecessary, except for some very rare cases). This means that a single flashed GPU would (theoretically) be compatible with several iMacs, with some caveats. As long as each iMac's boot drive has a properly configured installation of OpenCore Legacy Patcher, and the iMacs are all GPU-compatible from a hardware standpoint, the same GPU should function in several computers.

Flashing the GPU's VBIOS ROM chip is required for many GPUs to even turn the internal screen on. It's not really necessary for most people to have a native boot screen because once you set up OpenCore Legacy Patcher on your boot drive, it will provide an emulated boot screen within a few seconds of startup anyway. The OpenCore boot selector functions much the same as the native one does, and it even works on the internal display. You'll likely need to install OpenCore Legacy Patcher for your display to turn on (and to upgrade macOS beyond High Sierra) if you use a WX7100.

Windows will have native graphics acceleration, as it can use pre-existing Windows GPU drivers, although flashing the GPU VBIOS and using OpenCore Legacy Patcher are still recommended, even for a Windows-only machine. Mac OS typically has more problems with graphics acceleration, but the WX7100 is a modern, AMD/Metal, macOS-supported GPU, so it will have full graphics acceleration.

Summary: In case you'll be using OpenCore for booting your iMacs the GOP VBIOSes will be just fine for you. The EG VBIOSes only come in handy when the boot drive fails - and is required for legacy BIOS booting into Windows.

 

[Antonio Gerson B. da Cruz]

iMac Late 2009 to Mid 2011 graphics card upgrade
(Lastest update 01/16/2022)

This is not a plug and play solution! You need extended macOS / Unix system administration knowledge, the ability to run programs from the Terminal app and some manual skills to assemble your iMac again. If you have not done this before, get some local help in advance and make a complete plan and make notes while reading through this page and thread!

It is HIGHLY recommended that you read through this post before asking questions. Then, reread the information.

Before you post a question please add a signature to your account settings reflecting your machine type, graphics card, and possible even the problem you have. This signature sticks with every post you make and helps other to keep track and understand what is going on.

Please do not harass the BIOS developers to go faster, release a particular BIOS, etc. Please do not clog up the thread with useless posts asking if your specific card will get a new BIOS. It takes several months of reverse engineering and testing before getting a new BIOS working.

Spoiler: Important Information Before You Begin - Which Card to use?

There is no simple best card: Your budget, your comfort level with doing modifications, your ability to live with unresolved issues, your computing needs, the local market, your iMac model, etc. will determine the card to be used.

Unfortunately, this thread cannot help you source cards as there are too many variables involved.

Read through this information carefully in order to choose the best card for your needs.

1. The modified (NVIDIA video) BIOS with EFI boot screen version require an Intel i3 CPU or better (see also below #5). Same applies to AMD EG BIOS versions offering EFI boot screen.
2. The AMD GOP vBIOS version using OpenCore to provide a boot screen work perfectly with the Late 2009 27 iMac10,1.
3. Only Nvidia Kepler GK104, GK106, GK107, GK208 cards or AMD Baffin, Ellesmere, Polaris20, Polaris21 and AMD GCN cards will work in these iMacs with macOS including Big Sur. No other GPU variant has macOS driver support.
4. There are smaller MXM-A cards and bigger MXM-B cards running stable only in the 27" models. While all cards may function in a 21.5" model, the big ones are unstable due to their high power draw. Do not try it!
5. All big NVIDIA MXM B cards, the WX7100, and the RX480 need the big three copper pipe MXM-B heat sink from the 27" mid 2011 model with the 6970M card to get the generated heat out of the system under load. No exception!
6. Core2Duo CPU systems: Tests with iMac10,1 21.5" Late 2009 and iMac9,1 24" Mid 2009 and the Late 2009 27 iMac10,1 with a new GPU have been made. External displays worked in any case, internal LCD within the 27 Late 2009, the others needed you to buy a special driver board and connect the internal screen with the external miniDP port (and make it an external one). One user reported the internal LCD would work after letting the system sleep. Check carefully which driver board you might need. Some other cards may work with the stock BIOS showing all the seven problems... work is ongoing. This is a vBIOS problem. Another user installed a Nvidia GT120 successfully in his 27" iMac10,1 using the Apple BIOS made for the former A1224/A1225 models. This card is Tesla based and offers no metal support.
7. The fan control is broken after replacing the GPU. While we can monitor the GPU temps using different software solutions the Apple internal SMC (System Management Controller) refuses to control the ODD fan according to the heat generation on the GPU and heatsink. You need to use either the Macs Fan Control software or replace the ODD temp sensor. See below in the The Seven Problems section and read the #7 description.

Spoiler: Issues with Unsupported PC MXM Card (The Seven Problems)

Most - if not all - of these problems have been solved with the published BIOS versions.

Using a non Apple video card within an iMac will create these seven problems.

1. The loss of EFI boot screen;
2. The loss of backlight control;
3. You can only connect one external monitor to 27" iMacs;
4. The loss of Target Disk Mode;
5. The loss of Target Display Mode (TDM); (works only with High Sierra and before)
6. The loss of running the built-in Apple Hardware Test (AHT);
7. The loss of temperature sensors on the new GPU. But there is a hardware solution!

1. Boot Screens are now available on all listed cards using custom VBIOS and/or OpenCore

You may use the OpenCore booter to add a boot screen feature to every card - even the Nvidia and AMD cards not listed here or known to have no BIOS support to show the original apple boot picker.
There is a small delay between the chime (POST) and the initialisation of the actual boot screen on the current NVIDIA modded BIOS. Most of the time (such as a warm reboot in macOS) the system boots too quickly for the EFI portion of the BIOS to initialize, making it appear that you may not have a "boot screen." All is working as intended if you can hold the "Option" key at startup and get a boot picker.

2. Native Brightness control is available for cards marked with + or ++ using a combination of custom BIOS and OpenCore.

For other cards, brightness control may be added in the future. Be aware that without brightness control, the iMac display runs at full brightness by default. For higher powered cards and 27" models, this can generate a lot of heat.

If you would like to "dim" your display using color dimming, many have used the app Brightness Slider, which is available on the App Store for free.

You can also use this app, which works better than most apps in the App Store, because it will dim the colors on the whole screen and it will display the built-in OSD, just like native brightness control.

Additionally, hardware level modifications using a DyingLight module or a Raspberry Pi have been used for brightness control. This software written by @passatgt can be run on a Pi for backlight control. Another hardware solution can be found here.

Nvidia cards marked with ++ with native brightness control may notice their displays are not hitting maximum brightness control Potential. A kext modified by @highvoltage12v can be found here to fix this issue. It has been added to all installer packages and the Bit Sur patcher.

Last, but not least: User @Lottosmp came up with a solution based on the former engineering.

3. Despite having 2 miniDisplayPort outputs, the 27" 2011 iMac will only output to one external display. There is currently no fix or workaround for this.

4. Target Disk Mode is available on all cards marked with a + or ++!

5. Target Display Mode (TDM) is available on for cards marked with + when using both custom BIOS and OpenCore. Check this Q16 from FAQ about limitations.

6. Apple Hardware Test (AHT): There is currently no fix for running the internal service diagnostics. You may search the net for the ASD (Apple Service Diagnostic) package instead. For each system there is a different package. Download and install the package onto a SD card or a DVD, which will give you full functionality. A working download link may be hard to find. It is not open source.

7. GPU Temperature Monitoring is available on most new card when using both custom VBIOS and OpenCore. This shows the temps, but does not control the fans!
Use Macs Fan Control to control the ODD fan. Check the PDF attached to this post for details. The best solution as of today is to relocate the ODD sensor as described in this solution! The ODD sensor will drive the fan up using the Apple SMC software.

Spoiler: Table of Working NVIDIA Graphics Cards

Please read the issues section first! Most of these cards hit the street before 2012 and are considered as old cards.

Spoiler: Known issues or problems:

1. Old cards: A lot of the a 7-10 year old used Nvidia on the market may be already (half) dead. Some sellers offer cards with new BIOS - but to small - chips soldered on. Ignore those offers. If you cannot get video output working on internal and/or external displays face the bitter truth: The card may be DOA (dead on arrival). We are not a support organisation. Get your card returned and please do not waste (your and our) time on it!
2. iMac 2011: Some NVIDIA GPU may not run well in your 27 Mid 2011 iMac. We have reports of 880M, K3000M, K3100M, K4100M, K5000M which all run only without the internal LCD connected. As soon as you connect the LCD the system refuses to boot or ends up in boot chime loop. Sometimes the same error is related to connecting and disconnecting the single internal SSD. Meanwhile we believe the root cause are address conflicts on the SMBUS caused either by the GPU or some IC on the card connected to the SMBUS delivering thermal date. Sometimes you can visualize such problems with tools like HW Monitor. If you find additional weird temperature readings you might have such a card. No software solution possible!
3. Memory type: NVIDIA cards can have different memory types (Hynix AFR, Hynix BFR, Elpida, Samsung). Take a look at the links within the tables to find your fitting BIOS. For some cards - although listed below - we may not have the correct memory versions prepared.
4. Black Screen: After complete installation of the iMac the internal LCD can stay black, only three status LED light up. This is the black screen software issue. Normally you can get around it (temporarily) by pressing alt/option on boot. Late 2009 system you will face (only there) a more severe variant. After a PRAM reset the LCD gets and remains black. To fix this for all iMacs a kernel extension needs to be patched at best in advance. Only after booting into this patched macOS the internal LCD will come back. Use this package installer to solve this issue with all NVIDIA cards on all systems up to macOS Catalina. Do not use this package on Big Sur and later. Alternatively OpenCore (e.g. OCLP) with agdpmod=vit9696 in the boot-args fires up the LCD after a PRAM reset or GPU change, too.
5. Color depth problem: Happens on after boot - just sent the system once to sleep or change resolution. This solution or this opencore based solution may cure the problem.
6. Brighness level: Solution is linked here for all ++ cards and described by @nikey22 on each of his posts, again.
7. Brightness control with OpenCore: All + cards need OCLP or CL to enable brightness control and this solves the black screen issue using the agdpmod=vit9696 in the boot-args at the same time.

Spoiler: Table of NVIDIA Kepler GPU and vBIOS links

Card	BIOS	BIOS	Boot Screen	Brightness Control	21.5/27/MXM	Heat Sink Mod	OGL	MET
Quadro K500M			no	no	yes/yes/A		n/a	n/a
Quadro K510M			no	no	yes/yes/A		n/a	n/a
Quadro K610M +	ROM		yes (OC)	yes (issue 7 above)	yes/yes/A	special install	505	n/a
Quadro K1100M +	ROM	Elpida	yes (OC)	yes (issue 7 above)	yes/yes/A	no	907	n/a
Quadro K2100M +	ROM	Elpida	yes (OC)	yes (issue 7 above)	yes/yes/A	no	1229	n/a
Quadro K1000M +	ROM	noBC	yes (OC)	yes (issue 7 above)	yes/yes/A	no	903	n/a
Quadro K2000M +	ROM	noBC	yes (OC)	yes (issue 6 above)	yes/yes/A	no	797	n/a
Quadro K3000M ++	ROM	ROM1	yes (natively)	yes (issue 6 above)	no/yes/B	yes, BIG 2 pipe	1164	15
Quadro K4000M ++	ROM		yes (natively)	yes (issue 6 above)	no/yes/B	yes, 3 pipe	1680	n/a
Quadro K3100M ++	ROM	ROM1 ROM2	yes (natively)	yes (issue 6 above)	no/yes/B	yes, 3 pipe	1779	21
Quadro K4100M ++	ROM		yes (natively)	yes (issue 6 above)	no/yes/B	yes, 3 pipe	2465	32
Quadro K5000M ++	ROM	ROM1	yes (natively)	yes (issue 6 above)	no/yes/B	yes, 3 pipe	2038	29
Quadro K5100M ++	ROM		yes (natively)	yes (issue 6 above)	no/yes/B	yes, 3 pipe	2404	n/a
GTX 680M ++	ROM		yes (natively)	yes (issue 6 above)	no/yes/B	yes, 3 pipe	n/a	n/a
GTX 765M +	ROM		yes (OC)	yes (issue 7 above)	no/yes/B	yes, 3 pipe	1428	n/a
GTX 770M +	ROM		yes (OC)	yes (issue 7 above)	no/yes/B	yes, 3 pipe	2140	n/a
GTX 780M +	ROM		yes (OC)	yes (issue 7 above)	no/yes/B	yes, 3 pipe	2642	41
GTX 780M ++	ROM		yes (natively)	yes (issue 7 above)	no/yes/B	yes, 3 pipe	2642	41
GTX 880M ++	ROM		yes (natively)	yes (issue 7 above)	no/yes/B	yes, 3 pipe	2700	n/a
GTX 860M ++	ROM		yes (natively)	yes (issue 7 above)	no/yes/B	yes, 3 pipe	1616	34
GTX 870M ++	ROM		yes (natively)	yes (issue 7 above)	no/yes/B	yes, 3 pipe	2326	40

OGL column: OpenGL performance based on the Unigine Valley score from this table. T
MET column: Metal performance based on MetalBench score from the table.
OC: OpenCore

*
BIOS by @Nick [D]vB that currently enable boot screens on your iMac.

+
BIOS by @Nick [D]vB, @nikey22, and @Santa's Little Helper that currently enable boot screens on your iMac. Using OpenCore (through OLCP or Catalina Loader for High Sierra and Sierra) these cards offers right now native brightness control, target display mode, support of UEFI Windows 10, and more!

++
BIOS by @nikey22, and @stephle that currently enable boot screens, native brightness control, target display mode.

Notes:

1. Most if not all of these cards have a WSON type BIOS chip which cannot be programmed using a clip. You need nvflash with Windows or Linux. Take a look at the FAQ Q3 about flashing cards.
2. Audio support with UEFI Windows 10 would make OpenCore for any listed card necessary!
3. To enable brightness controls in UEFI Windows 10, see this post and this more recent post.
4. Target Dispay mode works only with High Sierra an older!
5. Latest working macOS is Monterey Beta 6. Beta 7 discontinued Nvidia Kepler support but OCLP starting with version 0.2.5 is able to patch support back. This patching does not bring 100% functionality back, e.g. OpenCL support in Photoshop is missing on Monterey

Spoiler: Thread about NVIDIA Maxwell and Pascal GPU (Windows and Linux and High Sierra, only!)

Regularly we get the requests about the more modern Nvidia Pascal and Maxwell GPU cards. Unfortunately Apple never supported these cards on more recent macOS versions. In case you plan to use such a GPU you will have to install the so called NVIDIA web drivers to get High Sierra support.

On the other hand these GPU are perfectly able to run Windows and likely some Linux distribution with full driver support. So if your focus is Windows only take a look at this offspring thread.

You will find special vBIOS versions searching this not so long thread.

Spoiler: Working (new) AMD Graphics Cards

Spoiler: Table of AMD Polaris+ GPU and vBIOS links

Please read the issues section first! These cards have been introduced 2016 and later and are considered as new cards. The GPU type is more power efficient compared to Nvidia Kepler and has by far higher metal performance.

Spoiler: Known issues

General: Some AMD cards will not POST (Power On Self Test) and will not run in the 27" Mid 2011. This happened with some WX7100 models, all RX480, some HP AMD cards.

1. AMD WX7100 and RX480 and RX470 (mobile)
   Currently we assume that only cards with a version number of 1.1 (search for a print on the front side of the card like V1.1 or VER 1.1) will post and run in an iMac12,2 (Mid 2011) while the version 1.0 will only run in Late 2009 and Mid 2010. RX470/RX480 cards are version 1.0 only - and do not work in Mid 2011 iMac systems!
2. AMD WX4170 (mobile)
   Some come with a blank EEPROM and are missing a resistor network. Working models with EEPROM are scarce. You can add a BIOS chip following this post. It requires soldering skills (ask cell phone repair shops)!
3. AMD WX4130/WX4150 (mobile)
   There are multiple versions of this card - only the green "Dell" branded versions currently work in every supported iMac model except the iMac11.2. Other cards like the blue HP WX4150 needs this mod to work in the 2011 iMac12,2 27 inch models. The Dell and HP cards need this additional mod to work in the iMac11,2 and iMac12,2 21.5 inch models. Check your card before applying any mod.
4. problems with cards: Unlike the NVIDIA family where we get each week several reports of dead cards we had so far only two reports showing a not properly working Dell WX4150 and a HP WX4170 - the problem have been solved by adding more VRAM support. Unfortunately we now have to chose from several published versions.
5. Initial setup: Using High Sierra the GOP vBIOS disables the internal LCD on power on.
   Work around: Use an additional external display on boot.
   If you plan to use High Sierra on a regular basis you need to implement this hard wire mod.

Card	BIOS	BIOS	Boot Screen	Brightness Control	21.5/27/MXM	Heat Sink Mod	OGL	MET
AMD WX4130 +++	old	ROM1	yes (OpenCore)	yes (natively)	yes/yes/A	special install	1805	53
AMD WX4150 +++	old	ROM1	yes (OpenCore)	yes (natively)	yes/yes/A	special install	1805	62
AMD WX4170 +++	old	ROM1	yes (OpenCore)	yes (natively)	no/yes/B	special install	2156	73
AMD RX480 +++	old	ROM1	yes (OpenCore)	yes (natively)	no/yes/B	yes or no?, 3 pipe	2800	150
AMD WX7100 +++	ROM	ROM1	yes (OpenCore)	yes (natively)	no/yes/B	yes or no?, 3 pipe	2949	160

OGL column: OpenGL performance based on the Unigine Valley score from this table. T
MET column: Metal performance based on MetalBench score from the table.

+++ These AMD cards are much more modern, but are difficult to source. Check the online offers carefully (the differences are explained above). The cards are be supported natively with Sierra and later. Latest known working macOS version is currently Monterey Beta 10.

GOP and OpenCore boot screen:

Using the GOP BIOS (links within the table above) you will have native brightness and and get an emulated boot selection only with OpenCore (see below). OpenCore enables 4K H.264, and huge 4K HEVC decode/encode by using the iMacPro1,1 ID. This hack makes your iMac look alike a new machine and gives you similar features. Does not work with Sierra when using OpenCore (add the -no_compat_check to boot-args to enable booting Sierra).

EFI boot screen:

Using the EG BIOS version you will get a native Apple boot picker with an iMac firmware modification on an additional external display, only. These BIOS versions offer native brightness control, too. You can also use the same OpenCore setup as with the GOP BIOS versions to enable 4K H.264/HEVC. Here you will find new EG BIOS versions for the WX4xxx line. Both solutions have their own advantages.

Adding a hot wire mod described in detail in the great post you can get the EFI boot screen visible on the internal LCD, too.

How to flash:

Cards can be flashed using a clip or amdvbflash with Linux or Windows or EFI. Take a look at the FAQ Q3 about flashing cards.

AirPlay:

AirPlay to Mac works with these cards installed on Monterey! AirPlay in general with Mojave and Catalina. Big Sur and later broke this.

Spoiler: Table of AMD GCN GPU and vBIOS links

This table shows cards with experimental support. Cards have been published between 2012 (M4000) and 2016 (W6170M).

- most cards still cause a crash on wake on iMac12,x systems (disable sleep)
- you need OpenCore (OCLP 0.3.3) to setup and run those + cards, no EFI boot picker available
- check the vBIOS links for more details.
- all cards support AirPlay with Catalina on all iMac11,x and iMac12,2
- some cards cause additional SMBUS address problems (W6170M, W5170M), CPU thermal readings are partly broken (hardware issue, needs modding the card)
- W5170M does not run properly in the iMac11,2, use the M5100 (hardware issue, needs modding the card)
- There are other models like the M4000, M6000, and W7170M - we have still no experience using these!

Card	BIOS	Boot Screen	Brightness Control	21.5/27/MXM	Heat Sink Mod	OGL	MET
AMD M4000	ROM	yes (OpenCore)	yes (natively)	yes/yes/A	special install	809	19
AMD M6000	ROM	yes (OpenCore)	yes (natively)	no/yes/B	2 pipe MXM-B	1010	30
AMD M5100	ROM	yes (OpenCore)	yes (natively)	yes/yes/A	special install	983	31
AMD W5170M	ROM	yes (OpenCore)	yes (natively)	yes/yes/A	special install	778	31
AMD M6100	ROM	yes (OpenCore)	yes (natively)	no/yes/B	2 pipe MXM-B	1024	30
AMD W6170M	ROM	yes (OpenCore)	yes (natively)	no/yes/B	3 pipe	1805	57
AMD W7170M					3 pipe

OGL column: OpenGL performance based on the Unigine Valley score from this table.
MET column: Metal performance based on MetalBench score from the table.

These AMD cards have been published between 2012 and 2016 and use macOS HD7000 and HD8000 driver stack. The cards are supported natively with 10.8.3 and later. Latest known working macOS version is currently Monterey.

Spoiler: Questions and Answers

Spoiler: Q1: Is this easy? I need a quick fix for my iMac!

A: Not necessarily. This "fix" is more of a "mod" to revive our iMacs. Depending on your scenario, it will require a full iMac disassembly, knowledge of BIOS flashing, dremel tools, heatsink modification, careful handling of logic board components, system administration at a higher level and some Unix or terminal command line awareness. Please make a plan before jumping into this!

Spoiler: Q2: System boots up, but no display, my GPU is not recognized. What do I do?

A: Your MXM card is likely running an incompatible BIOS and will need to be flashed with the correct one. This can be done from within Windows or Linux using NVFlash, or with a CH341a programmer. Some HP cards do not contain any BIOS and will not show up in the system until flashed (sometimes only possible with a CH341A clip!)

Spoiler: Q3: Flash VBIOS? How do I do that?

A: BIOS can be flashed in one of three ways:
1. Use a hardware CH341a clip programmer with free flashrom software. You can use the flashrom software directly from the MacOS terminal following this installation guide. Only AMD cards and a few NVIDIA cards like the K610M, K1000M and K2100M cards can be used with the clip. Experienced users may solder a different BIOS chip onto those cards to be used with a clip, too. All other NVIDIA cards have so called WSON BIOS packages and need software flashing.
2. Use a Linux USB pen drive. @xanderon created and @The_Croupier updated a pre-configured Linux USB image that can flash all Nvidia and all AMD cards in the iMac with Linux over SSH. Many have found this the easiest method. It needs a direct wired Ethernet connection between iMac and Router and can be used remotely from an SSH client when the iMac display is still dead. SSH clients are available for iPad, iPhone and other tablet devices, too. If you cannot connect to your iMac using the ssh command because of this message WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! delete the known_hosts file entering this terminal command: rm ~/.ssh/known_hosts.
If your router does not provide an IP automatically to new devices on the local network check and change its config.
3. Use Windows 7: @jowaju created a simple Installer package that can be run on macOS Sierra (10.12) and higher that creates a 15GB Windows 7 Bootcamp partition with all the needed tools. You may need to update software tools.
Notes:
AMD flash software and NVIDIA flash software is only available on Windows and Linux.
THIS external POST helps describes the flashing process. Others have found THIS POST useful.
Do a PRAM reset after flashing if you cannot boot into a known to work MacOS version!

Spoiler: Q4: OK, so I need to use the NVIDIA web drivers, right?

A: No - all cards outlined in this guide use the included NVIDIA drivers in macOS. No additional GPU drivers are needed.

Spoiler: Q5: Why aren’t you using Maxwell or Pascal cards in the iMac?

A: Recently iMac compatible vBIOS version for some Maxwell and Pascal cards have been published on this thread. macOS Mojave (10.14) deprecated support for the NVIDIA Web Drivers which allowed the use of Maxwell and Pascal cards. So these cards are perfectly fine for Windows and Linux. For now, Kepler GPUs and the (new) AMD cards seem to be our path forward when using Mojave or more recent macOS versions up to Monterey.

Spoiler: Q6: Can I use a 4K display with these cards? The original card doesn't support 4K.

A: Yes! So far, the K1100M & GTX 770M have been tested firsthand and successfully provide 4K@60Hz output via mDP to DP adapter on a 4K display. Others should work just as well.

Spoiler: Q7: What paste is recommended to cover the VRAM/Components on the MXM card like Apple’s design?

A: For the GPU Die any thermal Paste like Thermal Grizzly’s Kryonaut paste is good for the Die. For onboard components, many recommend using K5 Pro Viscous paste instead of thermal pads, due to the unevenness of the heatsink, it’s also similar to Apple’s original design. You can get it from the Bay or from the Book Store, too. How to apply the paste, watch this video!

Spoiler: Q8: What kind of performance can I expect after installing one of these cards?

A: We are still aggregating GPU benchmarks. There is a special section on this page and we added to the GPU tables a relative (to the old flagship HD6970) performance column only based on the the OpenGL benchmark.

Spoiler: Q9: Are there any internal modifications needed for an MXM-A swap?

A: For an MXM-A swap (the shorter/less power draw cards) there are no modifications that are needed for the heatsink on both the 21.5" and 27" model iMacs. The new X-clamp still needs be removed from the back of the card and have the screw posts drilled or tapped out in order to fit the heatsink's screws. Separate the X-Clamp using a hair dryer before drilling or tapping - it is just glued to the board. Skipping this step can fry or damage your card. If you've cleaned your heatsink, be sure to re-apply thermal pads around the GPU VRAM to prevent contact with the bare metal of the heatsink. Use electrical tape to isolate card components from the sink! Watch closely after installing the card. Take a look at the attached pictures of this post! In case you had a ATI card using a small Apple X-bracket (all MXM-A cards, 4850 and 5850) just reuse this bracket!! It fit's perfectly with all MXM-A , all NVIDIA and all AMD GCN replacement cards! The big Apple x-clamp can be used with the RX480 and WX7100.

Spoiler: Q10: Are there any additional internal modifications needed for an MXM-B swap?

A: The MXM-B cards only work on the 27" models due to power restrictions. There is one additional mod needed to make the MXM-B card fit. First you must grind down your heatsink in the area where one or two large coils sit, this way the card will sit flush with the heatsink. You must prepare the the X-clamp in the same way as described with MXM-A cards above. In case you had a ATI card using a small Apple X-bracket (all MXM-A cards, 4850 and 5850) just reuse this bracket!! It fit's perfectly with all replacement cards except the RX480 and WX7100!
If you have a 2 pipe heatsink that came with the lower end GPUs on these iMacs and want to use an MXM-B Card, you'll have to buy a 3 pipe heatsink to cool cards properly.

Spoiler: Q11: After GPU change my system does not boot at all, what is wrong?

A: Most likely the installation of card on the heat sink caused a short, or the card is simply faulty, or the card has not been reseated in the slot properly, check all this out first. Any hardware issue has to be solved by yourself!

Spoiler: Q12: How to control the fans according to the internal temperatures?

A: We all know that none of the modifies BIOS versions for the Metal GPUs listed in the table above is able to provide the internal GPU temperature back correctly to by used by the iMacs internal Apple SMC software to control the (ODD) fan according to the GPU internal temperature. To address this issue we recommended strongly to use a free software called Macs Fan Control. But you can also try to solve this problem by using the ODD temp sensor.

Spoiler: Q13: What is graphics acceleration and video acceleration?

A: The first term simply describes the fact that you can use GUI related operations like moving, resizing, closing an application or Finder window fast and smooth. This has been a serious issue with all patched installations of macOS versions on unsupported hardware. All "metal" cards listed above offer full graphics acceleration. Especially with Big Sur this has become more important since only "metal" enabled cards offer now the full graphics acceleration. The term video acceleration describes the hardware abilities of the GPU supported by the macOS. Only the new AMD GPUs offer 4K HEVC and 4K H.264 if installed in an iMac. If you want to know more about the possibilities AMD cards offer watch some of the videos collected here.

Spoiler: Q14: I have a color depth issue with my NVIDIA++ card. How to solve this?

A: This issue has been described by the author of the BIOS on every publishing post. So it is a BIOS issue which can be solved by just sending your iMac once to sleep and on wake up the graphics driver will re-initialise and the color mapping will be correct or you simply use this little app made by @passatgt and follow his instructions.

Spoiler: Q15: How to enable brightness control with Windows on Nvidia based systems?

A: Take a look at this post...this is not a plug and play task.

Spoiler: Q16: How to I get the target display mode working?

A: This feature is only officially supported until High Sierra on the iMac. To use it you need a working High Sierra partition/container on your boot disk. Apple dropped TDM support for M1 systems using thunderbolt ports (iMac Mid 2011 and later). You will not only be to use an iMac up to Mid 2010 as an external display for these new 2020+ machines. Check this thread for more details. For older Intel based systems until 2019 you will need the Apple Thunderbolt 2 (Mini DisplayPort female plug type) to Thunderbolt 3 converter cable (USB-C plug type).

Manually triggering of TDM is now possible for 2010 iMac in newer MacOS. Please see this post.

Spoiler: Q17: I want to help and experiment, what can I do?

A: First, read the recent part of thread and this post on a regular base. Staying on top of the progress here is key! And of course every user may help sharing his knowledge to new users - but please stay on topic!

Spoiler: Update your (mac)OS on the metal capable iMac

Spoiler: Using OpenCore on your iMac

What is OpenCore?

OpenCore (OC) is software to enable some features and to provide necessary data before an unsupported or supported macOS boots. This way we can solve sleep/wake and black screen issues without modifying (aka patching) the original Apple macOS installation itself. The most easy way to use OC is by using the OCLP tool.

The Highlander rule applies here (There can be only one OpenCore installation in a single EFI partition on your iMac). Having installed OpenCore to several EFI partitions can break your installation seriously and with weird side effects. So take a note where you put this software and keep track of if!

Important advices: DO NOT IGNORE!

AMD GPU users with a GOP vBIOS have no EFI Boot screen! So they cannot control the boot selection on boot! OpenCore offers a boot picker for those cases. The settings to boot OpenCore are stored in the PRAM. Reset the PRAM or installing a new invalid OpenCore version or changing the config manually may fail - and you loose your boot picker which may leave your system unbootable. How to get around this problem?

1. Lately we discovered how to create a OpenCore Recovery CD. You can create one in advance or using OLCP on a different machine even after loosing a working internal OpenCore installation. After a PRAM reset you can force booting the CD pressing the C button on power on. This way you can avoid maintaining a High Sierra fall back partition.
2. Alternatively you may install OC on the Catalina Loader using and SD card or USB stick (which can be pulled out in case of trouble), test all new OpenCore versions or config changes on this external installation. Your fallback will be booting into a supported macOS version like High Sierra. Create at first a small 30-50GB partition on your SSD and install High Sierra there using HFS+ (not APFS) and make sure that after a PRAM reset the iMac boots always into this High Sierra installation (so it has to be the first partition on the disk, I assume!). Later create other partitions where you can manage all APFS containers for Mojave, Catalina, Big Sur, and Monterey or install UEFI Windows.

If something goes south with either OpenCore or the unsupported macOS version you can always simply do a PRAM reset to get OpenCore out of your NVRAM and boot into High Sierra - and restart your journey. If things break seriously you will have to pull the disk out of the iMac to force boot of an external device. This can be avoided by having the OC on the CL on an SD card or USB thumb drive which can be pulled out of the system.

Owners of NVIDIA cards with an EFI Boot screen can install the EFI folder directly to the EFI partition of the internal disk (process described in the OCLP docs). Having an EFI Boot screen one can always boot without OpenCore just by pressing alt/option on boot and selecting a supported macOS version like High Sierra.

Why using OC or OCLP!

1. Native and unpatched installation of Mojave, Catalina and Big Sur with OpenCore Legacy Patcher (OCLP)
2. Brightness control with K610M, K1100M, K2100M, GTX765M, GTX770M, (GTX780M) cards
3. Emulated boot picker for all systems using AMD cards or NVIDIA cards having no EFI vBIOS!
4. WINDOWS 10 UEFI installations on Mid 2011 sound patch
5. AMD Video acceleration 4K HEVC and 4K H.264
6. OTA (over the air) Apple software upgrade on Monterey, Big Sur, Catalina, and Mojave.
7. AMD DRM (HW support) for Netflix (not in Safari), AppleTV, Amazon Prime etc. streaming
8. solves black screen issue with all NVIDIA GPU (using agdpmod=vit9696 in boot-args)

Where to get it and how to use?

Download: OpenCore Legacy Patcher (Use the TUI, do not use the GUI version!!)

For more details check the section below: Upgrade your (mac)OS on the metal capable iMac

More Information:

Thread: macOS 11 Big Sur on Unsupported Macs
Thread: macOS 12 Monterey on Unsupported Macs
Thread: OpenCore on Legacy Apple Hardware (focusing on MacPro, but also a lot of general instructions)
Thread: Activate AMD hardware acceleration

Videos: How to maintain OpenCore
Full documentation: Dortania OpenCore.

History:

Catalina Loader (CL) is another software allowing OC to be installed and maintained more easily than on hidden EFI partitions

Download (for Sierra and High Sierra): Catalina Loader image and original OC version
Post: The original OpenCore post on this thread
Guide: Guide by @Herrdude
Guide: Using Catalina Loader on an iMac

Spoiler: Installing Windows 10 on your iMac

OpenCore can only boot UEFI installations. Legacy installations will not show up in the OC boot picker. Because we need OpenCore for most graphics cards UEFI installation is the best choice.
Follow this link to install Windows using the UEFI method or search the net for more ways to achieve this. You will need OpenCore to enable the sound on 2011 systems using this method! To avoid blue screen issues on the iMac12,x read this doc. In case you lost your Windows EFI boot entry accidentally after installing OCLP take a look at this post how to recover it.

Users of UEFI Windows installation should check the contents of the internal EFI folder. You can both install OC and MICROSOFT sub folder in EFI. Using OCLP TUI choose 14. Advanced Patch Settings, for developers only, then 4. Set Generic Bootstrap and finally 2. EFI/BOOT/BOOTx64.efi. Then go back to the main menu and 1. Build OpenCore and 2. Install OpenCore to USB/internal drive.

Spoiler: Installing older supported macOS versions your iMac

According to this list the (Kepler) Nvidia drivers are part of macOS since 10.8.3. You might check this out on your own. At least on recent successful upgrade of an iMac 12,2 with macOS 10.10 can be reported here.
According to this GPU buyers guide the new AMD will be supported with macOS Sierra and later.

Spoiler: Installing macOS Sierra (supported)

Supported MacOS version can be installed using the original Apple installer. To avoid the black screen issue install this package.

Spoiler: Installing macOS High Sierra (supported)

Supported MacOS version can be installed using the original Apple installer. To avoid the black screen issue with NVIDIA cards install this package. To avoid APFS preboot corruption of other Big Sur or Monterey installation use HFS+ for High Sierra!!

Installing this last supported macOS version brings in the latest firmware. There will be unlikely ever new firmware versions since High Sierra went out of Apple support in Summer 2020.

Using an AMD GPU you need to install OpenCore using the latest OCLP. This way you can use all the superior functionality of the AMD GPU and avoid any possible problems like sleep/wake issues! Possibly one needs the agdpmod=vit9696 boot-args entry to enable the internal screen with AMD Polaris/Ellesmere cards on High Sierra using OCLP, this does not apply to GCN cards!

Spoiler: Installing macOS Mojave/Catalina/Big Sur/Monterey using OpenCore (unsupported)

The recommended method for AMD GPU users is to have High Sierra on a HFS+ partition as your primary OS and install Mojave/Catalina/Big Sur alongside on a separate APFS partition. So if anything goes wrong, you can still boot back into High Sierra to fix issues. Make sure it is the partition the iMac boots in after a PRAM reset automatically! Another method come get around this is having an OpenCore recovery CD prepared.

You have a single patcher option for all new macOS versions based on integration work of @Ausdauersportler into the tool provided by @khronokernel and @dhinakg! It can be used to install macOS Big Sur as well as Mojave and Catalina. After installing OpenCore your system will be qualified to run the stock installer programs provided by Apple.

• OCLP (this package offers a recent OpenCore package and enables installation of most recent macOS versions)

We recommend all new users to use OCLP. This is the future proof solution. First read the documentation linked on the download page.

The OCLP patcher TUI app will auto detect your system, BT, WiFi card and GPU. Carefully check in Build OpenCore step if everything has been detected properly. It generates a config specifically for your particular system and your GPU. You cannot use the config on other different iMacs! First install the new GPU, than install OCLP!
Having a Metal GPU makes your iMac Late 2009, Mid 2010, Mid 2011 fully compatible, again. All necessary WiFi, Ethernet, Sound, BT drivers will be injected using OCLP.

If you plan to use/install High Sierra or Mojave or Catalina using OCLP follow the manual approach described below.

Spoiler: Selecting OCLP settings manually - only for experts!

If you plan to use/install High Sierra or Mojave or Catalina using OCLP enter the Patcher Settings and

1. set SMBIOS Mode->moderate
2. disable Securebootmodel by SBM->False
3. disable SIP with setting SIP->False

This is currently unsupported by the OCLP dev team but it works like a charm. You can set everything according to your needs and even generate configs for different systems by bypassing the auto detection. Start with changing the model.

After Mojave/High Sierra installation you can fix the PreBoot/Recovery of both these macOS versions and reset SBM and SIP to true. This way you can use OCLP to boot into High Sierra, too. It enables the superior 4K HEVC and 4K H.264 as it contains the brightness control patches. No need to fix a Catalina installation!

Reboot, press alt/option and select the OpenCore on boot. Make it default by pressing CRTL.

Known Issues with Catalina:

• OTA update with OpenCore will only work if your are using the VMM flags as needed for Catalina described here (needs config.plist editing!!)
• OCLP 0.2.5 and later changed to shikigva=128, Catalina needs 80 to have working DRM. Go back to 0.2.4 or manually edit the config.plist when using later versions.

Known Issues with Big Sur 11.3+:

• the kernel sometimes stops working during the installation process due to a race condition. You can force a reboot and proceed with the installation normally. This might fail in rare cases. This happens on all iMac11,x systems and is not a patcher issue - this is an Apple bug or feature. As of today this bug has been fixed by the SurPlus OpenCore patch. This patch has been included only into the latest OCLP 0.3.0 nightly build. So to use this fix on iMac11,x you will either have to manually edit your config.plist as described on the SurPlus thread or just upgrade to the latest OCLP.
• using Big Sur/Monterey and High Sierra on APFS on the same machine can corrupt the Big Sur/Monterey preboot volume and prevent it from booting properly. Take a look and this post for a solution. You will disable the mount of the Big Sur volumes when starting High Sierra. The best approach is using High Sierra on an HFS+ partition!
• Using a AMD41x0 on Big Sur breaks screen recording (use a third party app). This happens even with supported systems.

Known Issues with Monterey:

• 12.1+ broke booting, again. A fix has been included into OCLP 0.3.2 (currently nightly development build)
• use the latest version of OCLP with Monterey
  but it broke lately iTunes/Apple Music support on pre Monterey systems. So you may consider 0.2.5 and later as the Monterey version of OCLP.
• Kepler support has been dropped
  solution: patching back Kepler support has been introduced with OCLP
• on Monterey all old BT devices stopped working!
  solution: hardware upgrade with BCM94360CD or similar (HandOff, Continuity)
  solution: use latest OCLP 0.3.1+ with BT fixes
• on Monterey all old WiFi devices stopped working!
  solution: hardware upgrade with BCM94360CD or similar (HandOff, Continuity)
  solution: use latest OCLP 0.3.1+ and apply WiFi post install patches
• on Monterey even supported BT and WiFi devices work unstable

Known issues OCLP:

• Use the TUI version with complete hardware detection, do not use the GUI version, there are always some settings not available just to avoid novice user confusion (this is why there exist a GUI just to hide details and sometimes features, too)!!

Notes:

1. Do not update a @dosdude1 patched installation of Mojave or Catalina, please backup user data, make a clean installation, restore user data.
2. The stock Atheros WiFi and old BT works with both options, too. No HandOff and no Continuity, of course.
3. AMD based systems offer 4K H.264 and 4K HEVC with Big Sur, again. DRM is working again and so Apple TV will show movies online, Netflix (currently not in Safari), Amazon Prime and others should work, too.
4. Nvidia based systems cannot get iGPU based H.264 QuickSync acceleration back on Big Sur!! It is currently not included into OCLP! So no Airplay using these dGPU on 2011 systems.
5. OCLP can be used without any patching and if offers SIP, File Vault and most importantly OTA upgrades. No other tool can offer this!
6. AirPlay will work with AMD dGPU and Mojave and Catalina using the original Atheros WiFI card. Big Sur needs a Broadcom upgrade. No tests made with NVIDIA dGPU.

Spoiler: Installing Mojave and Catalina with dosdude1 patchers (NVIDIA, 2011, QuickSync)

This is a legacy patching instruction. We strongly recommend to use OCLP to install any macOS Mojave and later. This section is only important for users of Mid 2011 systems with an NVIDIA card needing Intel QuickSync (H.264 encoding) to work.

AMD users will use the AMD GPU superior H.264 encoding and do not need Intel QuickSync. So an AMD user will never need to install using this method and have to use OCLP!

The recommended method is to have High Sierra as your primary OS and install Mojave/Catalina alongside on a separate partitions or APFS container partition. So if anything goes wrong, you can still boot back into High Sierra to fix issues. High Sierra offers a working recovery partition, too.

This is a two step installation. First you will use the @dosdude1 patcher and later install a package needed to address the hardware changes you made by changing the GPU.

Spoiler: Installing macOS Mojave (unsupported)

1. You could preinstall Mojave before changing your GPU. Use dosdude1's Mojave patcher to do the install.

Important: While running the Post Install tool, make sure you deselect the Legacy Video Card patch option (since you will using a new, compatible metal graphics card).

2. GPU and machine related patches: (see next section common macOS problems)

Late 2009, Mid 2010: To avoid the black screen issue install this package or follow instructions this post.
Mid 2011: Install this package to avoid sleep problems, black screen etc. or follow this post.

Spoiler: Installing macOS Catalina (unsupported)

Important: Post-install patching has changed since Mojave.
Patching is automated if your SMBIOS is detected to be an unsupported machine. Currently, only the 2011 iMacs have the "Legacy Video Card Patch" disabled by default. You will avoid this patch (since you will use a new, compatible metal graphics card) and will need to modify a plist file if you are using a 2009/2010 iMac with a Metal compatible video card or more easily while building the patcher, you can go to the "Options" menu and de-select "Auto-Apply Post-Install Patches" to avoid this.

Important: While running the Post Install tool, make sure you deselect the Legacy Video Card patch option (since you will using a new, compatible metal graphics card).

1a. The process for Catalina is similar to Mojave as mentioned above. Use dosdude1's Catalina patcher to do the installation.

1b. Getting the latest Catalina installer is broken with the latest @dosdude1 patcher. You need the gibMacOS utility to download the latest version and construct it from the several download files. Follow the instructions coming with the tool. Then in can be installed using the latest @dosdude1 patcher. This method works for all recent macOS versions!

2. GPU and machine related patches:
Late 2009, Mid 2010: To avoid the black screen issue install this package or follow instructions this post.
Mid 2011: Install this package to avoid sleep problems, black screen etc. or follow this post.

See next section to manually fix this issue if you have accidentally installed this patch. Best option is reinstalling Catalina from the scratch!!

Status 05/07/2021:

• DRM is known to work and you can watch Apple TV and Netflix on your iMac with AMD GPU, only.
• use gibMacOS (download code on green button and read the online docs) to download the latest and last full Catalina installer (19H05). A complete installation recipe has been published here...
• (using NVIDIA GPU) the Intel H.264 iGPU acceleration is still working on the 2011 models
• (having a 2011 system) installing @dosdude1 and later sleep patches found on post #1
• (having a 2009 and 2010 system) disable auto install patches in advance otherwise the legacy video patch make the fresh installation unusable
• security upgrades using the @jackluke OTAfix trick (latest Beta security upgrade is 19H505)

Spoiler: Some Common macOS problems and solutions when using dosdude1 patchers

After every MacOS update only when using a @dosdude1 patcher you will have to do the patching explained here to avoid common problems, again. Installing kernel extensions to the system is not an easy task. A complete installation guide to do this has been published (see link below with Q2). You can do this using the provided installer packages, using some tools or using the terminal and command line.

Q1: I get a black or blank screen on boot, how to fix?

A: Sierra and later has been causing "black screen" issues for many folks. This is caused by a lack of kext initialization due to a lacking board-id in the AppleGraphicsControl.kext (short AGC). A patched AGC kext and a further explanation can be found HERE, thanks to @highvoltage12v. Please look and the next question and link to get the installation guide, needed. Using some Nvidia cards in late 2009 iMac causes extra pain. The internal LCD will come up only after installing the patched AGC and booting into the newly patched MacOS. The BIOS versions will need a fix to come around this additional problem.

Q2: Sleep is broken and QuickSync is not working on my iMac 2011 in Mojave and Catalina, how do I fix this?

A: Solution for Mojave and Catalina, the SandyBridge kexts are missing. Installing them fixes sleep, but causes extended boot times. @highvoltage12v has provided the needed patches containing the SandyBridge kexts in THIS POST which can be installed. You can also simply install this Catalina package or this Mojave package.

Q3: After installing Catalina on my Late 2009/2010 iMac my animations are broken/choppy, the Dock is grey and the menu bar isn't translucent. How do I fix this?

A: The @dosdude1 installer automatically executes the "Legacy Video Card Patch" leaving Late 09/2010 MXM swapped users with broken/choppy animations. If you did install Catalina and would like to manually reinstall the stock Kexts and Frameworks, a guide has been written by @highvoltage12v to manually overwrite the patched files with stock files. Another more easy fix is the reinstallation of Catalina with auto-patching disabled.

Spoiler: Plan of the Complete Hardware Upgrade Process

You will find a short but hopefully comprehensive plan of the complete process in this post #14900. It included also a tools section.

Spoiler: About Hardware Problems during the Upgrade Process

You may face all kind of hardware problems while and after assembling your iMac again. There is an incomplete list of common (hardware) problems including the links to the original Apple iMac Technician Guides (iMac or more apple hardware) to trouble shoot such problems. You might use Apple Hardware Test (AHT) or Apple Service Diagnostics (ASD) to check your hardware.

Some other possible modifications as USB3 or WiFi/BT 4.x replacements may interfere with a new GPU.

Please understand that we cannot remotely repair or identify broken hardware. And there is no proof possible that hardware is broken. Do not ask for one. You may likely buy a dead used card. Check it before!

And this thread is not a support organisation for sellers of dead GPU cards. Do not abuse this thread and the people spending their time here to answer and help, please just get a replacement for your dysfunctional card!

Spoiler: About graphics card performance

1. OpenGL

OpenGL performance can be measured using the free Unigine Valley. Use these standard settings as resolution of 1920x1080, quality Medium, stereo 3D disabled, Anti-aliasing Off to compare results.

2. Metal

Metal has been introduced in 2012 hardware (HD4000 and NVidia GPU). Use GeekBench5 Metal or the more meaningful MetalBench software (Catalina and later).

Table of Benchmark Software and upload and result forms

Software	Download	Upload Form	Result form
Unigine Valley OpenGL	download Valley from here	upload results here	view results here
Geekbench5 Metal	download GeekBench5 here	upload results here	view results here
MetalBench Metal	download Metalbench here	upload results here	view results here

Apple M1 (MacBookAir) Unigine Valley 57.5 FPS, 2405 Score

Spoiler: Open exciting projects

Here a list of related external projects:

• MXM carrier board with PCI extender to plug in an eGPU into 27 Late 2009-2011 iMacs

This is a short list of enhancements worth to be realised IMHO:

• modify iMac Late 2009 i-series firmware to avoid total eclipse (black screen) (solved with OpenCore with agdpmod=vit9696 and since we use OpenCore for all Mojave+ installations it could be considered as solved!)
• add support for Early 2009 iMac10,1 models with MXM slot
• add support for AMD GCN cards (M4000, WX5170M/M5100, W6170M/M6000/M6100, and more). These will not offer VideoToolbox Support for Video Editing (4K HEVC and 4K H.264) but may will be more future proof than NVIDIA Kepler cards. All these cards break sleep/wake in iMac12,x (mid 2011)!

For those about to solder or code, we salute you!

Here the most frustrating (vBIOS or hardware or software) problems:

• why do VER 1.0 AMD MXM cards still not POST in the iMac12,2 2011 system ( RX480, WX7100) (card hardware or iMac BIOS issue)
• AMD GCN GPU break sleep on iMac12,x systems (while Ubuntu Linux supports sleep/wake using these GPU type, so this is clearly a macOS issue).
• some AMD GCN GPU have problems to sync with external displays (need display sleep to sync)

~~~~~~~~~~

Original Post from @MichaelDT June 14th, 2013.

I will be attempting to upgrade the MXM card in my 2011 21.5 iMac from the factory 6770m 512mb to a NVidia 675m 2GB. I choose this card because the chipset already has support from 10.8.3 onwards and affordability for an experiment. I am hoping that it will work without flashing like many of the other non MXM modern graphics cards (UEFI support) do in 64bit EFI Mac Pros ( I may loose the initial boot screen). But if all else fails I will attempt a flash. I will report back my findings when the card arrives (from Hong Kong). Wish me luck hopefully this will give those of us with the last modular iMac a path forward.

The AMD 6100 ROM link points to AMD 5100 ROM. Another question is, what about the RED PCB M6100?

 

[m0bil]

As I understand it, the difference between the BIOSes is a lower base clock. Is there a tool where I can easily set the clock speed of the Bios and try something in between, to find the maximum clock speed providing stable operation? Emphasis on easy boys!

Have you tried Wattman or Afterburner? Don’t know if they work on AMD Polaris cards…

 

[vinaypundith]

Hi,

I was planning to flash my iMac firmware to install a WX7100 but I saw that you could integrate the modules in the GPU VBIOS
I would be very interested because I also have 2 other iMacs on which I plan to use AMD cards (WX4130/50), with external screen for boot-screen, that would avoid me to flash their firmware and I don't need Windows (from what I understood, no graphics acceleration under Windows) Thank you

(Edit: I just realized I totally misunderstood what you were trying to say, and most of what I wrote is stuff you already know)

Yeah, you understood right, you can avoid the iMac firmware modification by using the VBIOS that has the modules integrated into the GPU VBIOS itself.
You will still need to do either the backlight wire modification or use an external monitor to get the boot screen.

The consensus here appears to be that using OpenCore for the boot drive selection menu is the best solution - personally I find this not to be the case, since I am often reinstalling macOS, replacing OpenCore itself, booting from external drives, installing Windows, booting Linux, etc, all of which would be quite a headache to do if you're relying on OpenCore and don't have the native Apple boot picker. However, with the AMD GPUs, if you would rather not do hardware mods, and don't need to do any of the tasks listed above, the OpenCore boot menu should indeed suffice.

 

[vinaypundith]

It is specific for iMac 2009 with W6170 and no boot screen
(and no OCLP boot picker) - my screen stays black until the
login screen - until now...

Without boot screen or boot picker an installation of a secondary
OS was difficult (High Sierra native & Big Sur patched...or WIN10).
Sometimes you only can bring the data to SSD with a secondary
iMac, HDD copy station or some other dirty tricks...

...but only if you have a patched 3rd party video card !

Very nice job!
As a note to anyone else reading this, it should work on most 2009 through 2011 model iMacs with Intel Core I series CPUs - not just the 2009. Should apply to all iMacs and GPUs that the EG VBIOS and external-monitor-boot-screen thing.
I'm using a 2010 iMac with a Radeon WX4130 (Polaris) GPU and a similar wire modification, except with a switch instead of a relay. It works brilliantly well. This looks to be the exact same modification, just automated by the relay instead of having the user manually flip a switch.
If anyone saw the post I made about the wire mod that was linked on the famous First Post here - this is an automated version of that.

 

[vinaypundith]

My WX4130 works pretty stable now after some sudden black screens this morning. I patched again...now it seems to work. One obeservation: My valley score is comparable (FPS 40, Score 1672) to similar machines like mine. Surprisingly my geekbench 5 metal score is much lower then comparable machines - see copy of excel sheet attached. My score is only 11.864. Most of them have 19k. Any plausible explication why ?

Try simply putting the iMac in sleep mode once, waking it up, and running Geekbench again. Might sound like a dumb solution, but this same behavior (of low Geekbench scores) occurs on Mac Pro computers with desktop Radeon Polaris cards - RX580 for example - when booted through OpenCore. Sleeping it, then waking it and re-running Geekbench gives a normal benchmark score. Don't ask me how it works, but it worked on my Mac Pro

 

[vinaypundith]

In the end I took the easy way out, I don't need this Mac except for storage.

And frankly I wouldn't even want Apple to know that I'm using an operating system they don't approve of, that's why I abandoned the idea of installing Hackintosh and instead bought Windows 11 on my desktop computer.

However, the most important thing is that I couldn't be happier to have my beloved iMac up and running again.

Thank you all for your contributions!

Congratulations!
Honestly I don't think Apple cares one bit about running an operating system they don't approve of on their hardware. With Hackintoshes, you can say it's a violation of Terms of Service because it says "For use on Apple branded systems". But with updating an actual Apple computer to a newer OS, there is nothing in the Terms of Service that prohibits it. You're perfectly safe from a legal standpoint to update.

 

[vinaypundith]

I have the Mid 2010 27" iMac (11.3 model) with an upgraded AMD Radeon WX 4130 GPU with the EG VBIOS version, the corresponding iMac EFI BIOS mod, and the LCD backlight wiring mod for enabling the boot screen. macOS works like a dream, but Windows doesn't work right. I'm having a couple of issues:

(I have Windows 11 Pro build 22000.194 installed as a dual boot on the iMac's internal SSD, booting in UEFI mode, fresh install with boot camp, Intel chipset, and AMD graphics drivers)

- GPU driver doesn't install properly. Device Manager shows a yellow triangle, and a status saying Error Code 43 (screenshot attached). I don't know how to find out what the exact error that causes this is - does anyone know? I tried installing the latest drivers from AMD's website, including doing a "factory reset" in the driver installer.

-The internal display doesn't come on by default - I have to do the same backlight wiring mod (forcing it ON) that's needed for the iMac to show the boot screen. I have the backlight control line wired to a switch, that forces it ON in one position (for boot screen) and normal mod in the other position (which, when I'm using macOS, I switch it to after the OS finishes booting). If I try to flip the backlight to normal mode after Windows finishes booting up, like I do in macOS, the screen shuts off, unlike where macOS where the normal backlight control works.

Has anyone successfully ran Windows in UEFI mode on one of these Polaris cards with the EG VBIOS? Thanks in advance.

 

[m0bil]

I have the Mid 2010 27" iMac (11.3 model) with an upgraded AMD Radeon WX 4130 GPU with the EG VBIOS version, the corresponding iMac EFI BIOS mod, and the LCD backlight wiring mod for enabling the boot screen. macOS works like a dream, but Windows doesn't work right. I'm having a couple of issues:

(I have Windows 11 Pro build 22000.194 installed as a dual boot on the iMac's internal SSD, booting in UEFI mode, fresh install with boot camp, Intel chipset, and AMD graphics drivers)

- GPU driver doesn't install properly. Device Manager shows a yellow triangle, and a status saying Error Code 43 (screenshot attached). I don't know how to find out what the exact error that causes this is - does anyone know? I tried installing the latest drivers from AMD's website, including doing a "factory reset" in the driver installer.

-The internal display doesn't come on by default - I have to do the same backlight wiring mod (forcing it ON) that's needed for the iMac to show the boot screen. I have the backlight control line wired to a switch, that forces it ON in one position (for boot screen) and normal mod in the other position (which, when I'm using macOS, I switch it to after the OS finishes booting). If I try to flip the backlight to normal mode after Windows finishes booting up, like I do in macOS, the screen shuts off, unlike where macOS where the normal backlight control works.

Has anyone successfully ran Windows in UEFI mode on one of these Polaris cards with the EG VBIOS? Thanks in advance.


View attachment 1948113

I don't currently have UEFI windows installed on the iMac where I have the WX4130, but I'm planning to install it soon to test. Did you try with Windows 10 ? I mean the driver and backlight problem is Windows 11 specific ?

The Device Manager error 43 is a very generic driver related error, I'm getting it a lot in my testing of Nvidia Pascal vbios modifications, I think it's either because of driver crash or driver self-unloads when it detects something strange with vbios contents (I've found no way to get additional information on what's causing it exactly).

I guess the backlight problem may be fixed if driver worked. Have you tried older version of AMD drivers ?

 

[AirpodsNow]

The iGPU can cause sleep/wake issues if not disabled or patched. Since we could not successfully patch it in all cases on iMac12,x and it is of no use with AMD GPU we decided to disable it.

If your iMac12,1 still has a sleep/wake issue there will be most likely another hardware problem. The GPU is not known to cause such a behavior. Memory?

Just to close this kernel panic issue for those wondering in the future. I wasn't able to troubleshoot the reason. Also because it occurred on 2 separate iMacs with different screen sizes I assumed there couldn't be a hardware issue (unless the GPU I chose was the cause). Simply turned off the wake/sleep mode and the kernel panics went away (didn't show up in the last month).

 

[ailik]

Does anybody know, what could be the reasoning for this gray thin lines on the screen?
I thought it was the videocard, but now im using Nvidia k3100m, and those lines are still there.
Is this the lcd panel itself?
Is there a way of fixing it?

 

[Ausdauersportler]

Does anybody know, what could be the reasoning for this gray thin lines on the screen?
I thought it was the videocard, but now im using Nvidia k3100m, and those lines are still there.
Is this the lcd panel itself?
Is there a way of fixing it?

Connect an external display, if you get there these lines too you have a broken GPU. Otherwise a broken display cable or it needs to be re-seated.
It is not completely impossible to have a panel malfunction, thin vertical lines have been reported several times before.

 

[ailik]

Connect an external display, if you get there these lines too you have a broken GPU. Otherwise a broken display cable or it needs to be re-seated.
It is not completely impossible to have a panel malfunction, thin vertical lines have been reported several times before.

its only visible on the iMac panel itself.
Tried to re-seat it a lot of times, still nothing.
Just thought that maybe there's a way of fixing it, somehow... maybe someone have already messed with this problem, and found what causes this.

 

[Antonio Gerson B. da Cruz]

The AMD 6100 ROM link points to AMD 5100 ROM. Another question is, what about the RED PCB M6100?

So is that? Do the AMD 5100 bios and instructions work for 6100? Guys, it's a simple question. I've researched in this entire thread and found little things about it. nikey22 posted a Bios where he reports the 6100 working with broken sleep/wake. Then ins supported CGN AMD cards the Bios for M6100M heads to the bios of 5100. in the nikey22 post, he showed a red PCB, however, late Ausdauersportler mentions instructions to green PCB. Sorry if am I looking dumb but it's confusing for me. I'd appreciate any reply.

 

[internetzel]

I have the Mid 2010 27" iMac (11.3 model) with an upgraded AMD Radeon WX 4130 GPU with the EG VBIOS version, the corresponding iMac EFI BIOS mod, and the LCD backlight wiring mod for enabling the boot screen. macOS works like a dream, but Windows doesn't work right. I'm having a couple of issues:

(I have Windows 11 Pro build 22000.194 installed as a dual boot on the iMac's internal SSD, booting in UEFI mode, fresh install with boot camp, Intel chipset, and AMD graphics drivers)

- GPU driver doesn't install properly. Device Manager shows a yellow triangle, and a status saying Error Code 43 (screenshot attached). I don't know how to find out what the exact error that causes this is - does anyone know? I tried installing the latest drivers from AMD's website, including doing a "factory reset" in the driver installer.

-The internal display doesn't come on by default - I have to do the same backlight wiring mod (forcing it ON) that's needed for the iMac to show the boot screen. I have the backlight control line wired to a switch, that forces it ON in one position (for boot screen) and normal mod in the other position (which, when I'm using macOS, I switch it to after the OS finishes booting). If I try to flip the backlight to normal mode after Windows finishes booting up, like I do in macOS, the screen shuts off, unlike where macOS where the normal backlight control works.

Has anyone successfully ran Windows in UEFI mode on one of these Polaris cards with the EG VBIOS? Thanks in advance.


View attachment 1948113

Yes, that error 43 has always been plaguing the EG VBIOS versions. You should search the thread for this issue - @Nick [D]vB also struggled with it - and solved it but didn't tell what exactly was the solution: Feb 23, 2020 .

 

[Surf2bikes]

Just to close this kernel panic issue for those wondering in the future. I wasn't able to troubleshoot the reason. Also because it occurred on 2 separate iMacs with different screen sizes I assumed there couldn't be a hardware issue (unless the GPU I chose was the cause). Simply turned off the wake/sleep mode and the kernel panics went away (didn't show up in the last month).

I sourced the same card from the same supplier through AliExpress (I used your reference). I am observing exactly the same issue with my Elpida WX4130 in my iMac11,3 . Since I have disabled sleep mode the system doesn’t crash anymore. So I guess it’s related to the hardware. Other then that I am really impressed with video performance on this old iMac 11,3.