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

[Pacific1972]

Hi guys,

Like many, I've been quietly lurking this amazing thread and planning my GPU upgrade for my iMac. But alas, things didn't work as I'd expected and now I'm stuck with a black screen even after piecing together a guide. So here I am looking for some sagely guidance from the masters on what my next steps should be.

Long story shot, so I have a late-2009 27" iMac (A1312, EMC 2374) with a dead HD 4850. I reflowed the damned thing once, worked for half a year before giving up on me for the last time. Thereafter no reflowing attempts saved it. I then bought a 3-pipe heatsink, a GTX880M 8GB and an intel Core i7-860. I installed them and booted up the machine. No boot screen (expected) but it works (see image attached)! However I also noted that it was pretty unstable, some boots are successful and some aren't (black screen throughout). Some get me to the desktop but just hangs there. PRAM resets don't solve them. I guessed that it was probably a vbios issue since I have not yet flashed the latest rom.

Then I followed the following plan:

1. Disabled SIP
2. Backed up original roms using RomTool
3. Installed all packages (AGC, BacklightFixup, FakeSMC, vit9696) via Sierra and High Sierra Package Installer
4. Successfully flashed vBios from 80.04.F5.00.07 (first backed up) to FE.ED.00.C0.DE (by nikey22) using Linux Live USB by xanderon

Problem description:
Immediately after step 3, the black screen persisted and I never got to see the login page. In fact, I don't even know if it actually got there since hitting the keys don't make any sound. Step 4 was really just me trying my luck. PRAM resets at this stage does nothing either. I have ensured that SIP is disabled again after every PRAM reset (yes I've learnt how to do this completely blind since recovery mode page isn't visible either). I can still hear the startup chime each time, and peeking at the diagnostic LEDs (with LCD plugged in), the first 3 light up, last one for LCD remains dark.

I'm kinda out of ideas at this point. I have included more information in my signature below.

Excuse me, I'm not fully involved with iMac 2009, but do you have
a picture of your GTX 880M ? I think about different ROM Flash, I
have use CH341A Programmer with clamp for SOP8 BIOS Chip on
HP8300 WIN10 PC...

I've attached system information for you to compare - please look at
the IDs and ROM-version, but my A1312 is from 2011...

 

[peekpt]

Sorry Ausdauersportler, but no-one said that DHCP is not activated by default. I am convinced DHCP will work on xanderons boot stick in most cases. But in my case DHCP boot automation doesn't work (maybe network setup or whatever). And I strongly believe there are others also getting stuck at this point for some reason. I found some hints here in that forum. I tried different USB sticks, iMac is always connected via ethernet and I never changed configs on xanderons boot stick. And of course, I waited plenty of minutes to give GRML more than sufficient time to boot completely (went out with the dog i.e.). Situation is still the same and I can proof this easily by looking at GRML on internal display and keeping an eye on router information, only coming up for GRML by using key strokes described. This is not meant to confuse somebody and I really appreciate this thread and all the good work and information, especially your work Ausdauersportler (I am following you for good reasons). I am just glad to help Kranny36. I don't need to get this information on page 1 or in xanderons post.View attachment 1731970

Don't you have someone that borrows you a router to temporary connect host and client to the lan ports in order to get it working

 

[RobertL39]

There are a few recent HP cards coming without a chip. Take a look at the first post, we have seen WX4170 w/o chips. Normally the cards have a chip (because they are identical to the DELL counterparts), but the AMD cards are different, even in function.

And I can't tell how to verify that an HP card has a BIOS chip. The pictures in Post #1 talks about some of the cards not having one but the pictures in Post #1 are not labeled so I don't know where to look. Need a picture, and where the heqq on the card is it? I'm assuming the large, black modules on the card are the vRAM, since they are sometimes labeled "elpidia". But they're not the BIOS chip, are they? How can I verify from an eBay picture if the HP card has a BIOS chip?? THANKS!!!!
The "million miles away" is great. Like the Cover-Ups version, too. Thanks for that! Good guitar, for sure. But give me Stevie Ray Vaughn any day.

 

[searge]

Come on, I know what I am doing. Host and client are directly connected to LAN Ports (AVM FRITZ!Box 7490 or 7530 (at my girl friend)). Never had problems with both devices and DHCP is enabled.. this is getting stupid. I got my solution and this was also useful for another forum member. Just trying to help...

 

[ponte]

With regards to "Configure OpenCore to quickly boot into your default drive on every startup"

I didn't run OpenCore before installing catalina.

I managed to fix the sleep mode but still haven't fixed the (lack of) brightness controls nor the default boot disk.

Would I be able to fix this with catalina already installed? Any advice would be greatly appreciated.

Already went to the 1st post, but obviously the instructions are for before installing catalina. I referred to this section "Spoiler: Installing OpenCore on your iMac".

Can anyone provide a quick way of doing it? A package would be ideal if available. running my graphics card is the 610M.

TIA

 

[Ausdauersportler]

Come on, I know what I am doing. Host and client are directly connected to LAN Ports (AVM FRITZ!Box 7490 or 7530 (at my girl friend)). Never had problems with both devices and DHCP is enabled.. this is getting stupid. I got my solution and this was also useful for another forum member. Just trying to help...

I do not want to argue, but this solution was made to get over this blind flight typing of flashing commands and now - just because some guys cannot set up their routers correctly - we are back at this closed eyes approach typing other commands.

Then we could have made preconfigured scripts on the flash utility like K4100M, GTX780M, etc so you just need to enter the name of the card and everything happens on it's own - including backup

 

[peekpt]

With regards to "Configure OpenCore to quickly boot into your default drive on every startup"

I didn't run OpenCore before installing catalina.

I managed to fix the sleep mode but still haven't fixed the (lack of) brightness controls nor the default boot disk.

Would I be able to fix this with catalina already installed? Any advice would be greatly appreciated.

Already went to the 1st post, but obviously the instructions are for before installing catalina. I referred to this section "Spoiler: Installing OpenCore on your iMac".

Can anyone provide a quick way of doing it? A package would be ideal if available. running my graphics card is the 610M.

TIA

The steps are:
- download Catalina Loader and 0.6.6 open core files
- Download balena etcher
- Prepare an usb pen with at least 2g and drag dmg from Catalina loader into the Etcher , select usb pen and burn.
- copy the efi folder from 0.6.6 to the root of the usb you created.
- boot holding alt key select Catalina loader drive and do ctrl + Enter to make it default drive

 

[bielousov.com]

** NVIDIA GeForce GTX780M Mac Edition ROM **
Genuine Native Boot Screen & Brightness Control

View attachment 942195​

There are many members here that have this card now and have been using it with & without Opencore. The previous rom iterations did not initialize the “built-in” iMac LCD screen but instead spoofed it to use the Cinema Display as the internal screen which rendered brightness control non-functional, and forced the use of a bootloader to add the feature back via a kernel extension.


This ROM does not require a 3rd party bootloader like OpenCore.

ROM testing has already been underway for the past few weeks by @Ausdauersportler and @highvoltage12v.

There is an overclock present on the GTX780M from the base rom. I would suggest you to use a 3-pipe heatsink for this GPU. Apply proper thermal pads and appropriate heat dissipating grease like K5pro to the areas that are in contact with the heat sink. Keep mac fans up and running to achieve better control of cooling as well.

Brightness Control Stepping Modifcation

-Turn computer on, hold down Command(⌘)-R
-Choose Utilities > Terminal
-Enter:csrutil disable
-MacOS Catalina: requires you to make root writeable: sudo mount -uw /
-Reboot
-Download and open 'Kext Utility v2.6.6'

-Navigate to S/L/E (System/Library/Extensions)
-Copy "AppleBacklight.kext" to Desktop
-Edit: AppleBacklight.kext/Contents/Info.plist
-Scroll down to: IOKitPersonalities > AppleIntelPanelA > ApplePanels
-There you find several Apple LCD profiles.
-For the iMac 2011 27" machine locate:

<key>F10Ta007</key>
<data>
ABEABgALABQAHAAnADMAPwBOAFwAZwBzAIEAkQClAL8A2wD/
</data>

-Change the <data> section to:
ABEAAgA3AF8AigCzAOsBJAFnAakB1AIJAlQCogL4A00DlgRpBGk=

-Drag your modded kext into Kext Utility, allow it correct permissions
-Applebacklight.kext.bak folder will be created
-Reboot

The above data pattern will allow for a wider span of steppings for the brightness control and utilizes more of the capacity of the HD3000. If you have a different machine, your panel ID can be found by going to System Preferences > Displays > Color > Open Profile > mmod

There will be a separate instruction for Windows 10 users to adjust the RMBrightness scaling accordingly.

Caveats post-install/Bugs:
-16bit resolution glitch of UGA_DRAW_PROTOCOL - temporary solution: activate a sleep cycle and return, this should now clear the issue.

Important Links:
USB Flashing for SSH @xanderon method <link>
@Curtis Gross – walkthrough video <link>
Heat Sink MOD to grind down the edges <link>
Heat Sink mounting @tgaillar <link>
Kexts for sleep/iGPU (Mojave/Catalina) <link>



More GPU Roms to come... Enjoy!

First thing first, thanks a lot for making these patches, collecting and maintaining this knowledge base in an uptodate and easy to read state.

I've got a brand new 780M in 2011 27" iMac flashed with the ROM from the Linux USB bundle. It had partial boots screen (only after logo), no brightness control (even with kext patches) and with Catalina it often required PRAM reset to get rid of the black screen.

After reflashing with this ROM everything looks better: full boot screen, brightness controls work, temperatures on heatsink and PECI appear much lower (hardly ever go ubove 70C, not 80+ like they did with the other ROM), I could swear there's a slightly better performance too.

However, now under the heavy load (i.e. only in some games, e.g. Wasteland 3) I often get blue screens of death and kernel panic. This hasn't been the case for a fact with the other ROM, same OS same games. Did SMC and PRAM reset, didn't help, but lowering graphic details and turning on all fans does help it.

The issue doesn't occur in benchmark tests like MetalBench or Unigiene (Heaven, Valley) no matter how long they run, but also the heatsink doesn't go above 60C with them, although the results are matching those for my configuration.

May best guess would be that the built in overclocking now kicks in but the lack of GPU chip sensors fails to kicking the temperature throttling, or maybe my system kernel needs to be rebuilt? Improve cooling? I feel like sooo close to the end of this journey as everything else works fine. Any ideas on this issue?

 

[searge]

- just because some guys cannot set up their routers correctly -

This is simply rude and arrogant. Did we really came up this way? What makes you sure about that this problem refers to a wrong router setup (for me and for Kranny36)?
I checked this behaviour in 2 different households on 2 different routers. There are a lot of devices in both households getting their IP-addresses via DHCP every day. Hitting the key strokes as described also ends up in getting an IP-address for GRML. DHCP usually is activated by default in these routers. There is not much more than activating or deactivating this and defining address range.
This situation stopped this project for me for weeks as I am running on K3100M and depend on xanderons flash solution. Only getting a HD 6750m lighting up my internal display finally showed me what was going on.
I can invite you looking at this directly if getting near to Ostwestfalen...

 

[spyrant]

Excuse me, I'm not fully involved with iMac 2009, but do you have
a picture of your GTX 880M ? I think about different ROM Flash, I
have use CH341A Programmer with clamp for SOP8 BIOS Chip on
HP8300 WIN10 PC...

View attachment 1731965
I've attached system information for you to compare - please look at
the IDs and ROM-version, but my A1312 is from 2011...

Thanks for the reply! I don't have a picture of the GTX880M as it's a little troublesome to remove it back out (let me know if it's necessary). However I have *almost* the same system information GPU as yours (snapped a picture just before patching AGC). Does this mean we have the same GTX880M? From my understanding, mine is pulled out from a Dell Alienware laptop.

 

[Ausdauersportler]

This is simply rude and arrogant. Did we really came up this way? What makes you sure about that this problem refers to a wrong router setup (for me and for Kranny36)?
I checked this behaviour in 2 different households on 2 different routers. There are a lot of devices in both households getting their IP-addresses via DHCP every day. Hitting the key strokes as described also ends up in getting an IP-address for GRML. DHCP usually is activated by default in these routers. There is not much more than activating or deactivating this and defining address range.
This situation stopped this project for me for weeks as I am running on K3100M and depend on xanderons flash solution. Only getting a HD 6750m lighting up my internal display finally showed me what was going on.
I can invite you looking at this directly if getting near to Ostwestfalen...

What do you want to hear now? That you are not able to pin point a root cause and therefore have to come up with awkward solutions like this. I admit it works but it is not the idea of using this tool.

You solve a problem comes up rarely with this really nice Linux flash utility and „avoid typing blindly solution“ with another „typing blindly“ solution while the root cause is the router, not the iMac, not the Linux flash utility. This USB flash utility works fine for me over a year now used more than 500 times (during testing unreleased BIOS versions) and with three different router setups (changed during over the time), and obviously it is working for a lot of other unsung heroes on the thread, too. You have a problem which may occur more than once, but not in general.

Even a FritzBox (DSL router) has to be rebooted once in a while, needs updates and sometimes even refuses to connect to clients or even worse, refuses to connect to the provider. In that case I start working on my router setup, not my dozen clients.

EDIT:
If you have some more time to spend on the Linux GRML setup you may make it writable find a way to enter the personal WiFi data persistently and document it (on the same first post you made starting this discussion) and we can make it a router problem post and link it in to the first post. This would be really great! You already found out more than the most other users here. Changing to the flash folder at login would be nice, too.

 

[Ausdauersportler]

First thing first, thanks a lot for making these patches, collecting and maintaining this knowledge base in an uptodate and easy to read state.

May best guess would be that the built in overclocking now kicks in but the lack of GPU chip sensors fails to kicking the temperature throttling, or maybe my system kernel needs to be rebuilt? Improve cooling? I feel like sooo close to the end of this journey as everything else works fine. Any ideas on this issue?

There is no thermo throttling working if your GPU overheats unless you use Macs Fan Control or you have relocated the ODD sensor onto the heat sink. In that case the ODD fan will ramp up when the ODD sensor passes 50C.

This is the last and currently unsolved of the seven problems. While the latest versions of Macs Fan Control (like FakeSMC in some cases) are able to show the GPU temps even of the new NVIDIA and AMD GPU, the Apple SMC software itself does not read a proper temp from the GPU. I started some month ago gathering open source SMC software hacks, but the ODD replacement works like a charme, although I would like to see it kicking in more early...

 

[Afro_]

The GPU die temperature sensor problem!
​

You all know that none of the modifies BIOS versions for the Metal GPUs listed in the table on page #1 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.

A different solution has been described several times now and last week and was in the mood to reopen my iMacs again and did this simple mod.

I (carefully) separated the ODD temp sensor using my finger nails and placed it on the back side off the GPU sink (side by side with the sink temperature sensor). Then I used a simple and cheap two component epoxy alike glue and fixed the little sensor. During the first experimental phase I used just a 3M or Tesa strip to hold the sensor in place.

Spoiler: There may be a more simplistic approach:

Just cut off the two cables in the near the sensor and exchange the cable ends with the plugs connecting the same colors simply together (grey to grey and black to black). So you can easily connect the original heat sink sensor to the ODD connector in the logic board and vice versa.

Doing this you have a working fan control again even when doing system upgrades or during the start phase. As you may have noticed the Macs Fan Control used before is a user land application and it is only working after primary login to your account.

I attached some pictures showing the Macs Fan Control in automatic (i.e. SMC) mode under full Valley load (WX4170) and the hardware mod.

Notes:
Please use Macs Fan Control (or a similar software) in any case as a fall back if the replaced internal sensor fails of the glue does not hold it properly. It is a nice tool to monitor what is going on internally. HW Monitor using the FakeSMC extensions gives you graphs and

The SCM comes in at nearly 55 C of the ODD sensor. This is late compared to my former settings starting at 40 C. There are some websites writing about normal GPU temps, so everything below 70 is perfect, everything below 80 tolerable. But keep in your mind that endless gaming is burning Rom your CPU ....

Having a powerful GPU (780M, K4100M, WX4170 etc) will burn 70-75W and cause this amount of heat.

Hi, the maximum ODD fan speed for iMac 12,2 shown in the image is 2,500. Shouldn't it be 3,800? Anyone might know the possible reason for this?

 

[Pacific1972]

Thanks for the reply! I don't have a picture of the GTX880M as it's a little troublesome to remove it back out (let me know if it's necessary). However I have *almost* the same system information GPU as yours (snapped a picture just before patching AGC). Does this mean we have the same GTX880M? From my understanding, mine is pulled out from a Dell Alienware laptop.

Some Info:

VGA Bios Collection: Dell GTX 880M 8 GB | TechPowerUp
...perhaps you have a look at different ROM revision ?!

You have an unpatched Video Card and the BIOS Patch you made (?) was
not successful (look at ROM revision 80.04.F5.00.07 for CLEVO or DELL),
but this was not the BIOS from nikey22 !

GTX880M

Perhaps it's the best to patch it external with CH341A Programmer,
or you must use a method from page #1 of this thread ?

 

[spyrant]

Some Info:

VGA Bios Collection: Dell GTX 880M 8 GB | TechPowerUp
...perhaps you have a look at different ROM revision ?!

You have an unpatched Video Card and the BIOS Patch you made (?) was
not successful (look at ROM revision 80.04.F5.00.07 for CLEVO or DELL),
but this was not the BIOS from nikey22 !

GTX880M

Perhaps it's the best to patch it external with CH341A Programmer,
or you must use a method from page #1 of this thread ?

View attachment 1732237

Thanks! What I mean to say was that I took that screenshot *before* flashing anything. I don't have such screenshots after flashing since I've lost my display completely. I managed to flash a successful vBios from the original 80.04.F5.00.07 to FE.ED.00.C0.DE (by nikey22) using Linux Live USB by xanderon.

I actually lost my display after patching AGC using the Sierra and High Sierra Package Installer and this was before me even flashing the nikey22's FE.ED.00.C0.DE.

 

[Pacific1972]

Thanks! What I mean to say was that I took that screenshot *before* flashing anything. I don't have such screenshots after flashing since I've lost my display completely. I managed to flash a successful vBios from the original 80.04.F5.00.07 to FE.ED.00.C0.DE (by nikey22) using Linux Live USB by xanderon.

I actually lost my display after patching AGC using the Sierra and High Sierra Package Installer and this was before me even flashing the nikey22's FE.ED.00.C0.DE.

Hmm, do you have an USB Stick with DOSDUDEs High Sierra Patcher or alternative
Boot Source (another HDD / SSD) ?

Perhaps you have one or more incompatible KEXT files (System/Library/Extensions)
installed - that means sometimes no Boot or Black Screen... I've had something like
this a few month ago with useless KEXT files, but have alternative 2nd Boot partition.

With exchangeable Boot Partition you can go to the other partiton (S/L/E) and delete
faulty KEXT files (you can sort by date in finder and see actual installed KEXTs) !

 

[Grmacs]

I have an other graphic card with the winbons chip. I was not sure I f its possible to use the chip from an different Vendor or size. I have an other old graphic card with an winbond chip and i will desolder both and mount the Winbond Bios to the working graphic card with the MXL Chip.

thanks a lot for the replay. I will do the changes

Hi Chris, were you able to get yours up and running? I also have K1000M that doesn't have large enough chip for the 256K ROM file. I also noticed theres a blank area for another EFI chip it appears... I believe the K1000M is supposed to work natively but will not have the boot screen or boot camp screen, was that your experience? I believe the GPU I have is completely dead because swap with no firmware change caused boot loop and no image/backlight. I have another on the way but would still like to flash the ROM if I can manage it.

 

[Ausdauersportler]

Hi, the maximum ODD fan speed for iMac 12,2 shown in the image is 2,500. Shouldn't it be 3,800? Anyone might know the possible reason for this?

3800 rpm is the value I see with 2009 and 2010 systems, only. The 2011 iMacs and Macs Fan Control show a limit of 2500 rpm all the time.

 

[bielousov.com]

There is no thermo throttling working if your GPU overheats unless you use Macs Fan Control or you have relocated the ODD sensor onto the heat sink. In that case the ODD fan will ramp up when the ODD sensor passes 50C.

This is the last and currently unsolved of the seven problems. While the latest versions of Macs Fan Control (like FakeSMC in some cases) are able to show the GPU temps even of the new NVIDIA and AMD GPU, the Apple SMC software itself does not read a proper temp from the GPU. I started some month ago gathering open source SMC software hacks, but the ODD replacement works like a charme, although I would like to see it kicking in more early...

Makes sense, but I just reproduced the issue with ODD running at full 2,500rpm with Fan Control, running Unigene Valley for like 15 min on high settings. I guess if I can prove it happens faster with ODD on the lowest rpm, than it's definitely the overheat. But heat sink is surprisingly not too hot, so maybe something on the back site is boiling, or my thermopaste on the chip doesn't have great contact because of the thermopads on memory?

Anyhow it appears that ODD might not be enough, I'm exploring a possibility of adding another little fan to blow directly onto GPU. I've replaced DVD with 2.5 HDD with chassis a long time ago and have some room to mount it there, just not sure where to get the power from it. Thinking about ODD powering both fans…

But I guess you have me the eureka moment: it's not relocating ODD sensor, but relocating the ODD fan what might help. So I can take it off and mount to the HDD chassis, so that it'd blow to GPU or get an aftermarket one and still mount it to the HDD chassis and power from ODD. I'm fine about setting it to full throttle in Fan Control, it's the quietest one anyways. Any ideas about a fan that would work nicely instead of ODD, preferable higher rpm and reading rpms in Fan Control?

UPD: ok, was not able to reproduce with fans set to lowest and Unigene Valley running for 15 minutes at high settings, although heatsink temp grew to 84C (as opposed to 64C with fans on), so perhaps cooling is not the problem here.

Now that I'm thinking of it I was always getting the kernel panic when switching back to OS with Cmd + Tab, so could be some switching between OpenGL and Metal, or some issues with memory, now I'm clueless. I wish I'd try this in High Sierra, but kinda too lazy to install another OS.

 

[Ausdauersportler]

And I can't tell how to verify that an HP card has a BIOS chip. The pictures in Post #1 talks about some of the cards not having one but the pictures in Post #1 are not labeled so I don't know where to look. Need a picture, and where the heqq on the card is it? I'm assuming the large, black modules on the card are the vRAM, since they are sometimes labeled "elpidia". But they're not the BIOS chip, are they? How can I verify from an eBay picture if the HP card has a BIOS chip?? THANKS!!!!
The "million miles away" is great. Like the Cover-Ups version, too. Thanks for that! Good guitar, for sure. But give me Stevie Ray Vaughn any day.

You are really, really making things complicated. There is only a single HP card (WX4170) known coming sometimes without a BIOS. The best thing is, your cannot even find it on Ebay! There are some Far East resellers offering new NVIDIA cards with replaced BIOS chips which sometimes (rarely) have the wrong size. There are some NVIDIA GPU variants with more than one memory vendor type (possibly not supported by the the current vBIOS versions published here).

How about rethinking your strategy. Instead of summing up what can got south with all available cards just select one type, check the memory type, select a local source and choose resellers offering product return. We cannot bail you out of every deal and cannot zero the risk with such a deal at all. Most cards are used and I already put a warning on the first post.

No WX4170, no Far East resellers, no old card, only unused spares - minimum risk strategy. Try to find a AMD card!

BTW: The first post has plenty of links to follow - one points directly to the WX4170 picture. Try to read through it another time.

 

[RobertL39]

You are really, really making things complicated. There is only a single HP card (WX4170) known coming sometimes without a BIOS. The best thing is, your cannot even find it on Ebay! There are some Far East resellers offering new NVIDIA cards with replaced BIOS chips which sometimes (rarely) have the wrong size. There are some NVIDIA GPU variants with more than one memory vendor type (possibly not supported by the the current vBIOS versions published here).

How about rethinking your strategy. Instead of summing up what can got south with all available cards just select one type, check the memory type, select a local source and choose resellers offering product return. We cannot bail you out of every deal and cannot zero the risk with such a deal at all. Most cards are used and I already put a warning on the first post.

No WX4170, no Far East resellers, no old card, only unused spares - minimum risk strategy. Try to find a AMD card!

BTW: The first post has plenty of links to follow - one points directly to the WX4170 picture. Try to read through it another time.

Makes sense to me! Thanks again! Sorry to 'make things complicated' but I figure better clear than bricked.

 

[Ausdauersportler]

Makes sense, but I just reproduced the issue with ODD running at full 2,500rpm with Fan Control, running Unigene Valley for like 15 min on high settings. I guess if I can prove it happens faster with ODD on the lowest rpm, than it's definitely the overheat. But heat sink is surprisingly not too hot, so maybe something on the back site is boiling, or my thermopaste on the chip doesn't have great contact because of the thermopads on memory?

Anyhow it appears that ODD might not be enough, I'm exploring a possibility of adding another little fan to blow directly onto GPU. I've replaced DVD with 2.5 HDD with chassis a long time ago and have some room to mount it there, just not sure where to get the power from it. Thinking about ODD powering both fans…

I owned two 780M and used them nearly half a year without such problems. The most likely problem we had during the last year with all this MXM-B NVIDIA cards was this:

1. the users did not really manage to grind the holes for the big two R22 coils.
2. the users did not use the proper thermo paste with the GPU (like Artic MX-4)
3. users did not use the proper paste with memory and other parts (K5 pro)

Using pads instead of K5 pro is the worst thing you can do. It makes it impossible to get the GPU surface into contact with the copper part of the heat sink.

Since I cannot repair broken cards by writing posts or by applying software patches the only thing I can to is reminding the well known problems.

 

[Ri7]

3800 rpm is the value I see with 2009 and 2010 systems, only. The 2011 iMacs and Macs Fan Control show a limit of 2500 rpm all the time.

Yes, I've seen it before in 2009/2010 systems but I found this is possible in 2011 too.
The fan is fully capable to achieve 3800rpm.

In my tests with K4100m, I accidentally disconnect ODD sensor and voilè, ODD fan imediately shows 3800rpm.
With this speed all temperatures inside my iMac remais stable and low, even with 6 hours of 3D

My topic about this:

Weird maximum fan RPM values after each reboot

Hi all! My signature setup (with K4100m) is acting weird about fan speeds. Each time I turn on my system it shows different maximum rpm speeds for ODD and CPU fans. With K4100m GPU I really need maximum rpm from ODD fan, but sometimes it shows 3800rpm (that is OK) but sometimes it shows only...

forums.macrumors.com

 

[Ausdauersportler]

Yes, I've seen it before in 2009/2010 systems but I found this is possible in 2011 too.
The fan is fully capable to achieve 3800rpm.

In my tests with K4100m, I accidentally disconnect ODD sensor and voilè, ODD fan imediately shows 3800rpm.
With this speed all temperatures inside my iMac remais stable and low, even with 6 hours of 3D

My topic about this:

Weird maximum fan RPM values after each reboot

Hi all! My signature setup (with K4100m) is acting weird about fan speeds. Each time I turn on my system it shows different maximum rpm speeds for ODD and CPU fans. With K4100m GPU I really need maximum rpm from ODD fan, but sometimes it shows 3800rpm (that is OK) but sometimes it shows only...

forums.macrumors.com

Yes, I know, you can exchange the fans from 2009 to 2011 and vice versa. Have you tried to run the system without Macs Fan Control at all? Possibly this software limits the capabilities of the Fan? If this happens report an issue - at there website, of course

 

[peekpt]

I owned two 780M and used them nearly half a year without such problems. The most likely problem we had during the last year with all this MXM-B NVIDIA cards was this:

1. the users did not really manage to grind the holes for the big two R22 coils.
2. the users did not use the proper thermo paste with the GPU (like Artic MX-4)
3. users did not use the proper paste with memory and other parts (K5 pro)

Using pads instead of K5 pro is the worst thing you can do. It makes it impossible to get the GPU surface into contact with the copper part of the heat sink.

Since I cannot repair broken cards be writing posts or patching the only thing I can to is reminding the well known problems.

I remember reading a post about someone that used a 0.5mm copper shim because the cpu wasn't touching the heatsink.