Sapphire Radeon HD 7950

[pojavi]

Hi, thanks again for the tips. I will keep on eye on those temperatures, above all, the psu ones. I feel comfortable and safe when I configure gpu fans using mac fans control. However when it comes to psu fans, I think is dangerous to mess aroun with it if you´re not sure about what you´re doing. That´s reason why I asked about a solution not involving third party software. For example I have just turned on the cMP, and both fans, gpu and psu, were at 1800/1100 respectively. Too high for being at idle in my opinion.

After some minutes, it seems to go down a little, showing the stats that you can see in the screenshot. And it is is after a while, that the fans goes down a bit more. What it is for sure, is the fact that if I don´t set up the gpu fans with the app, the gpu rmp is no less than 1500. Too much again for being at idle. I don´t know if using high sierra solves the problem

 

[h9826790]

Hi, thanks again for the tips. I will keep on eye on those temperatures, above all, the psu ones. I feel comfortable and safe when I configure gpu fans using mac fans control. However when it comes to psu fans, I think is dangerous to mess aroun with it if you´re not sure about what you´re doing. That´s reason why I asked about a solution not involving third party software. For example I have just turned on the cMP, and both fans, gpu and psu, were at 1800/1100 respectively. Too high for being at idle in my opinion.

After some minutes, it seems to go down a little, showing the stats that you can see in the screenshot. And it is is after a while, that the fans goes down a bit more. What it is for sure, is the fact that if I don´t set up the gpu fans with the app, the gpu rmp is no less than 1500. Too much again for being at idle. I don´t know if using high sierra solves the problem

Understandable. Anyway, this is the setting I am using now.

For PSU, min 38C, Mac 55C. IMO, it's very safe. 55C is still very safe for a PSU, but that will command full fan speed (2800RPM) already.

Most of the time, my PSU will stay at around 40C with the fan running little bit above idle (system ambient just above 30C).

And even in summer time, the PSU never run above 45C with this fan profile.

Anyway, did you ever pull out the PSU and check if they are clean? Are dusty PSU can easily run 15C warmer than a clean PSU.

No need to open the PSU, just pull it out from the cMP, then you can see if it's clean inside. If not, give it a good blow.

Last but not least, before you use MacsFanControl to manually set anything. You may run Luxmark (recommend at least 15s), then wait for 3 min (let the cMP as idle as possible, do NOT use anything but just leave MacsFanControl open to monitor fan speed), and see if the PSU fan go back to idle. If yes, then that high PSU fan is really just a bug.

 

[pojavi]

Hi h9826790. I appreciate a lot this information. What app is this screenshot from?

Yesterday, I was able to draw some conclusions about how my cMP 4.1 flashed to 5.1 behaves.

Without any fans control, being at idle and just turned on, the cMP shows around 1600/1100 rpm to PCI/PSU respectively. As I said, very noisy and high in my opinion to be at idle. Above all, the fan which noise comes from near the dvd-drive. I think that is the PSU fan, isn´t it?. On the other hand, shows two temperatures for the power supply (PSMI supply 1 and 2 ), ¿are both of them important?.

If I don´t configure the gpu fun with mac fan control, the rpm won´t go below 1500 rpm. This issue can be easily controlled using the pci ambient sensor in mac fan control leading the gpu rpm to 800 rpm.

However the psu fans and temperatures are worrying me a lot. At idle, the psu rpm are 1100 (both psu sensors indicates between 30 and 38 ºC). It is after a big while, without any configuration whatsoever, that the rpm drops to the minimum but the second psu power supply temperature goes up to nearly 50 ºC. Is it normal this temperature?.

 

[h9826790]

Hi h9826790. I appreciate a lot this information. What app is this screenshot from?

Yesterday, I was able to draw some conclusions about how my cMP 4.1 flashed to 5.1 behaves.

Without any fans control, being at idle and just turned on, the cMP shows around 1600/1100 rpm to PCI/PSU respectively. As I said, very noisy and high in my opinion to be at idle. Above all, the fan which noise comes from near the dvd-drive. I think that is the PSU fan, isn´t it?. On the other hand, shows two temperatures for the power supply (PSMI supply 1 and 2 ), ¿are both of them important?.

If I don´t configure the gpu fun with mac fan control, the rpm won´t go below 1500 rpm. This issue can be easily controlled using the pci ambient sensor in mac fan control leading the gpu rpm to 800 rpm.

However the psu fans and temperatures are worrying me a lot. At idle, the psu rpm are 1100 (both psu sensors indicates between 30 and 38 ºC). It is after a big while, without any configuration whatsoever, that the rpm drops to the minimum but the second psu power supply temperature goes up to nearly 50 ºC. Is it normal this temperature?.

I owned two 4,1. And the PSU are different. Of course they look identical on the outside. But when look inside, they are clearly difference.

One of them has more empty space inside, the other one is more "occupied".

The one that emptier runs much warmer. Exactly like your ~50C during idle.

So, I suspect that's a normal behaviour for that version of PSU. However, I've already sold that one, so, can't do any test anymore.

The one that I am using now is the one that more occupied. May be the bigger electronic devices provide better cooling. No really sure about this.

AFAIK, the 2 readings are PSU ambient, and PSU components. In my case, PSU 2 aways higher, and that should be the PSU components temperature. However, it seems your PSU 1 is higher. Not sure if that's another PSU version, and the sensors are in different order / location. And it seems PSU 1 is the component temperature in your case.

The fan control software I use is from this thread.

https://forums.macrumors.com/threads/mac-pro-2009-2010-fan-control-now-version-2.1340705/

It's an open source software.

The one that I am using I never post, because it need more than just the fan control software itself. It also depends on some other SMC software to alter the target fan speed (which will override the system protection), but not like the original version that only alter the minimum fan speed (which will NOT override the system protection.

For this particular high fan speed bug, we need to assign a lower target fan speed to override the buggy high fan speed. Therefore, AFAIK, only MacsFanControl and TG Pro can work. All other fan control software won't help.

 

[pojavi]

ok thanks again for all the information. After having observed the psu temp behaviour during the last 2 days, I am almost sure that it must be a bug only solved using software.

As I said, rpm in psu fans are high just the moment I turn the cMP on, 1100 or 1200 rpm (leaving configuration auto in mac fan control). Temperature on both psu supply sensors are between 30 and 40 ºC. After a while, rpm goes down to 600 rpm (the minimum) and logically temps go up to 53 ºC. And that´s the way it behaves automatically everytime I turn the cMP on.

Gpu is configured to go always at 800 rpm acording to temps describred in the thread, but I don´t reallly know what´s the best configuration for psu using mac fan control. In the thread, each person says something different, but nobody know truly the way to configure psu temps.

 

[h9826790]

ok thanks again for all the information. After having observed the psu temp behaviour during the last 2 days, I am almost sure that it must be a bug only solved using software.

As I said, rpm in psu fans are high just the moment I turn the cMP on, 1100 or 1200 rpm (leaving configuration auto in mac fan control). Temperature on both psu supply sensors are between 30 and 40 ºC. After a while, rpm goes down to 600 rpm (the minimum) and logically temps go up to 53 ºC. And that´s the way it behaves automatically everytime I turn the cMP on.

Gpu is configured to go always at 800 rpm acording to temps describred in the thread, but I don´t reallly know what´s the best configuration for psu using mac fan control. In the thread, each person says something different, but nobody know truly the way to configure psu temps.

TBH, if your cMP naively allow the PSU run at 53C with idle fan, any fan speed above that can only make it safer.

The real question is just how much PSU fan noise you are willing to get.

And the PSU won't burn or anything even run at 60C. In worst case, just the capacitor will dry up quicker, which eventually cause the PSU fail. But that's fixable.

So, if your problem is the fan noise. IMO, it's definitely OK to use MacsFanControl to lower it a bit. Nothing danger.

But of course, that's your own choice.

 

[macstatic]

I found this thread after recently having bought a second-hand Sapphire Vapor-X HD-7950 (3GB) which I see others here are also using. I just replaced my old GPU card (ATI Radeon HD-5870) with it, powered up the cMP (5,1) and did a PRAM erase procesure (holding down ALT-CMD-P-R while booting until you hear a bootup chime sound) just to be sure, and it booted right into MacOS (10.13 High Sierra) as before. I didn't get the EFI boot screen though, so that's what I'm going to do next, once I figure out from this and other threads how).

But I have a couple of questions about the Vapor-X HD-7950 (I haven't been able to find the manual anywhere online):

1) is only one fan supposed to spin? Does the second fan kick in only when it's getting very hot?
2) Please explain the white switch at the bottom of the card. I understand it's for switching between two ROM positions, but which one should I set it to, and what do the different settings do?

 

[h9826790]

I found this thread after recently having bought a second-hand Sapphire Vapor-X HD-7950 (3GB) which I see others here are also using. I just replaced my old GPU card (ATI Radeon HD-5870) with it, powered up the cMP (5,1) and did a PRAM erase procesure (holding down ALT-CMD-P-R while booting until you hear a bootup chime sound) just to be sure, and it booted right into MacOS (10.13 High Sierra) as before. I didn't get the EFI boot screen though, so that's what I'm going to do next, once I figure out from this and other threads how).

But I have a couple of questions about the Vapor-X HD-7950 (I haven't been able to find the manual anywhere online):

1) is only one fan supposed to spin? Does the second fan kick in only when it's getting very hot?
2) Please explain the white switch at the bottom of the card. I understand it's for switching between two ROM positions, but which one should I set it to, and what do the different settings do?

1) No, both should be spining for 7950. If that stop, it's faulty.

2) For some cards, there is no difference at all. For other cards, usually just minor clock speed differences. Anyway, apart from the Sapphire HD7950 Mac Edition card (not your card), both ROMs should perform pretty much the same on your cMP.

 

[macstatic]

1) No, both should be spining for 7950. If that stop, it's faulty.

Hmmm... I tried something:
with the cMP side panel removed (so I could physically see the GPU) I powered down the computer, then powered it up again. I noticed that both fans started spinning, but the second one stopped after about 1-2 seconds. So at least the fan works and it's electrically connected to the rest of the board.
I don't have a PC, so I have no chance to test if it behaves differently in something other than a Mac.

2) For some cards, there is no difference at all. For other cards, usually just minor clock speed differences. Anyway, apart from the Sapphire HD7950 Mac Edition card (not your card), both ROMs should perform pretty much the same on your cMP.

Actually it appears that the white "switch" I found isn't a switch at all, but a piece of polystyrene!
So I don't know where it is, and will have to do some research to find it.
But basically you're saying that it makes no difference which position the switch is set to when in use, and neither when reprogramming the ROM chip (for adding the EFI boot screen).

 

[h9826790]

So I don't know where it is, and will have to do some research to find it.

 

[h9826790]

I noticed that both fans started spinning, but the second one stopped after about 1-2 seconds. So at least the fan works and it's electrically connected to the rest of the board.

May be some lubrication is required. Sounds like the initial "high speed test" is enough to spin up the fan, but once go back to idle, the internal friction is too strong which cause the fan to stop completely.

 

[macstatic]

View attachment 2146079
View attachment 2146080

Awesome! Thanks for checking.
I found it. It's a pushbutton, and if you push it in it the switch's "S" (Sapphire?) lights up in blue. Otherwise it doesn't light up at all.
I tried it in both settings but it made no difference at all, neither when the computer was already switched on (I expected perhaps a crash or something).

May be some lubrication is required. Sounds like the initial "high speed test" is enough to spin up the fan, but once go back to idle, the internal friction is too strong which cause the fan to stop completely.

Yes, I'll look into this. I also tried to see if it makes a difference to the fan with the two switch settings, but no difference at all.
I also tried to hold the fan back with my finger when spinning up and pushing it around when it had stopped, but to me it seems delibrate -that the GPU is deliberately controlling it to stop. Could it be that the ROM has been reprogrammed/hacked by the previous user(s) to spin up only when the temperature is high enough, or not at all (to keep noise down) -which of course is a bad idea.

Since the ROM is re-programmable and allows for the Mac EFI boot screen code to be added, is it also possible to get hold of the original ROM contents to "factory default" it?

 

[h9826790]

Awesome! Thanks for checking.
I found it. It's a pushbutton, and if you push it in it the switch's "S" (Sapphire?) lights up in blue. Otherwise it doesn't light up at all.
I tried it in both settings but it made no difference at all, neither when the computer was already switched on (I expected perhaps a crash or something).



Yes, I'll look into this. I also tried to see if it makes a difference to the fan with the two switch settings, but no difference at all.
I also tried to hold the fan back with my finger when spinning up and pushing it around when it had stopped, but to me it seems delibrate -that the GPU is deliberately controlling it to stop. Could it be that the ROM has been reprogrammed/hacked by the previous user(s) to spin up only when the temperature is high enough, or not at all (to keep noise down) -which of course is a bad idea.

Since the ROM is re-programmable and allows for the Mac EFI boot screen code to be added, is it also possible to get hold of the original ROM contents to "factory default" it?

TechPowerUp has plenty of VROM to download. You may go there to have a look. Most likely can find a factory ROM for your card.

Change ROM after power on has no effect, won’t cause any crash, that’s normal.

You can actually boot from ROM 1, then switch to ROM 2, and flash ROM 2. This is how we recover a damaged ROM on these dual ROM cards.

You may run Luxmark to stress the card a bit (Furmark is much stronger for 7950, don’t try that unless you know the 2nd fan will spin up), and see if the 2nd fan works.

 

[macstatic]

TechPowerUp has plenty of VROM to download. You may go there to have a look. Most likely can find a factory ROM for your card.

Cool! I assume this is a safe site so I won't be downloading something that could cause damage or problems.
I think I found it, in the "video BIOS collection" part of the website.
Looks like I have several (33!) BIOS downloads to choose from when searching for my 7950 card.
I'm guessing I need to first look for any physical printed sticker/label on the card to see the exact card model and perhaps even the installed BIOS first, in order to match the one to download.

Change ROM after power on has no effect, won’t cause any crash, that’s normal.

You can actually boot from ROM 1, then switch to ROM 2, and flash ROM 2. This is how we recover a damaged ROM on these dual ROM cards.

That sounds like a good idea. Have a modified BIOS (Mac EFI boot) in one switch position and the standard factory installed BIOS in the other position.

Would it be a good idea to first "factory reset" both BIOS positions with the default BIOS download?
In this case it's probably best to stick to your suggestion (above) where I "factory default" one ROM, reboot into that ROM to check if it's all OK, then continue by "factory defaulting" the other ROM.
From then on I can continue by adding the Mac EFI boot-screen to one of the ROM positions, and I would have a failsafe setup.

You may run Luxmark to stress the card a bit (Furmark is much stronger for 7950, don’t try that unless you know the 2nd fan will spin up), and see if the 2nd fan works.

For Luxmark, do you mean this (download page)? I expected a Windows app, but I see there's also a Mac version! I'll download it and take a look.(Apart from VirtualBox) I don't have a "native" Windows setup on my Mac, and I've learnt that you can't flash the ROM or similar things from a virtual setup.

Regarding one of the fans that just spins up for a second and stops again: maybe I should disassemble the GPU, then exchange the two fans. That should show me if the fan is the problem or the firmware that controls it (or the electronics for that particular fan).

 

[h9826790]

Would it be a good idea to first "factory reset" both BIOS positions with the default BIOS download?

Only if the 2nd fan restore it's normal function after you flashing the downloaded ROM.

I "factory default" one ROM, reboot into that ROM to check if it's all OK, then continue by "factory defaulting" the other ROM.
From then on I can continue by adding the Mac EFI boot-screen to one of the ROM positions, and I would have a failsafe setup.

This is what I will do if I get that card.

For Luxmark, do you mean this (download page)? I expected a Windows app, but I see there's also a Mac version!

I mean the Mac version, and you should see something like this if it can finish the 2min default benchmark.

maybe I should disassemble the GPU, then exchange the two fans. That should show me if the fan is the problem or the firmware that controls it (or the electronics for that particular fan).

Only do that if you have confidence about how to change fans. But if you can, that's not a bad idea indeed.

 

[macstatic]

I've downloaded the Mac version of Luxmark and am going to look into the reflashing soon, but first I have to make a Windows environment (I've struggled with Boot Camp in the past, but will try again -at least I managed to do a clean install of MacOS 10.13.6 on a "test" drive which I will use for all these upgrade things and testing before comitting to a newer OS with the new GPU).
So I found a nice article on how to create a USB flash drive installer for MacOS 10.13, and also how to do a clean install (I mistakingly thought you could only upgrade from earlier OS versions), but I wasn't able to do that with the new GPU, so I put the old one (HD-5870) back in. In hindsight it might be that the USB-installer took a very long time to load everything, so maybe it would work with the new GPU -I don't know. Maybe someone here knows which OS versions recognize "Metal" GPU cards, such as my 7950.

Anyway, I now have the 7950 Vapor X removed and thought I might as well look into the fan that doesn't spin (I don't want the card to risk overheating). I found a "disassemble" video on Youtube, and here (around 1:33) the PCB is removed from the heatsink:

Once this is done, should I remove/clean away all the existing thermal paste and apply a new one on the same spots?
As for the fans: it looks like they're cumbersome to remove, and maybe even the cable lengths are cut differently, so an easier way would probably be to apply the fan's correct voltage directly to the appropriate pins on the fan connector and see if each one spins properly.
Does anyone know which voltage they run on? (EDIT: according to this Vapor-X 7950 eBay fan-replacement seller, they're 12V fans).

 

[h9826790]

So I found a nice article on how to create a USB flash drive installer for MacOS 10.13, and also how to do a clean install (I mistakingly thought you could only upgrade from earlier OS versions), but I wasn't able to do that with the new GPU

Don't use USB. It will default to install Windows in UEFI mode, which will write a digital cert into the cMP's BootROM. That can't be removed by NVRAM reset, and effective a kind of BootROM corruption.

If you end up want to use Windows, just burn the ISO to a CD, then hold C to boot (you can do that with your HD7950). And install Windows natively in legacy mode to one of your spare drive. This is good enough for you to flash the card.

Once this is done, should I remove/clean away all the existing thermal paste and apply a new one on the same spots?

Yes, you should. And you better prepare some thermal pad. People often damage the thermal pads when they remove the cooler.

In general, only three situations that you don't need to re-apply thermal paste.

1) It's liquid metal, but not silicone base thermal paste.
2) It's graphite pad, but not silicone base thermal paste.
3) The thermal paste was newly applied (e.g. within few days, and still looks very "liquid" when you open it)

In all other cases, you better completely remove the old paste, clean up the surface, and apply new thermal paste.

Side topic, for this HD7950, if you want best cooling, you can actually go liquid metal. In my own experience, this can easily let the GPU run 10-15C cooler. But liquid metal itself is danger to the surounding electronic devices, and the cMP's case. So, you must handle that very very carefully. If don't want to take the risk, traditional thermal paste sure is good enough to do the job. This card has a very good cooler anyway.

 

[macstatic]

Don't use USB. It will default to install Windows in UEFI mode, which will write a digital cert into the cMP's BootROM. That can't be removed by NVRAM reset, and effective a kind of BootROM corruption.

If you end up want to use Windows, just burn the ISO to a CD, then hold C to boot (you can do that with your HD7950). And install Windows natively in legacy mode to one of your spare drive. This is good enough for you to flash the card.

I don't understand.
I just installed MacOS 10.13 (High Sierra) by first creating a USB-installer as described here.
Then I chose that USB flash drive as the startup drive and restarted my cMP. After a while I was presented with the installation etc. menu as described here, and I then installed 10.13 High Sierra on a hard drive I had installed inside the cMP (using a drive sled).

I haven't yet installed Windows, so I assume no harm is done so far?
Did you mean not to install Windows itself on an external USB drive (hard drive, SSD, flash drive etc.), or did you mean not to create an installer of Windows on an external USB drive of some kind?

If it's Windows itself I think I might have experimented with that on an external USB hard drive attached to a mid-2012 Macbook Pro. If I recall correctly I wanted to try out MacOS 10.14 or 10.15 without upgrading its (internal SSD) which runs 10.13.6 High Sierra.
Does this mean I might have ruined its BootROM, or does this only apply to the cMP?
Is there any way I can check either machine for this corruption? The cMP still has version MP51.0089.B00. I understand once I install the HD-7950 back in and attempt to upgrade the OS to 10.14 I will also get the BootROM upgraded. Will this fix any such issues by overwriting it with the correct data?

I was thinking of trying to install Windows via Boot camp today (on that "test" hard drive inside the cMP), but will hold off until I fully understand all this.
By the way, what do you mean by "install windows in legacy mode"? If I burn the ISO, then hold down C (to boot from the CD/DVD-ROM drive), will that run the installer from the CD?

Yes, you should. And you better prepare some thermal pad. People often damage the thermal pads when they remove the cooler.


In general, only three situations that you don't need to re-apply thermal paste.

1) It's liquid metal, but not silicone base thermal paste.
2) It's graphite pad, but not silicone base thermal paste.
3) The thermal paste was newly applied (e.g. within few days, and still looks very "liquid" when you open it)

In all other cases, you better completely remove the old paste, clean up the surface, and apply new thermal paste.

Side topic, for this HD7950, if you want best cooling, you can actually go liquid metal. In my own experience, this can easily let the GPU run 10-15C cooler. But liquid metal itself is danger to the surounding electronic devices, and the cMP's case. So, you must handle that very very carefully. If don't want to take the risk, traditional thermal paste sure is good enough to do the job. This card has a very good cooler anyway.

Thanks for all those tips. I've already started disassembling it by removing many of the screws, but haven't arrived at the step where you pull out the PCB from the cooler. Thankfully I got a better idea that I can try first..... instead of having to go through all of that (removing and re-applying thermal paste and graphite pads) I noticed that there's a small connector on the PCB which I believe might be for the two fans. I should be able to unplug the connector from the GPU's PCB, and once I find the pinout I could check each fan by applying some small power to the correct pins and see if they spin. At least then I'll see if the fan is OK or not.

 

[h9826790]

By the way, what do you mean by "install windows in legacy mode"? If I burn the ISO, then hold down C (to boot from the CD/DVD-ROM drive), will that run the installer from the CD?

Will, and the 7950 will display even not flashed.

I haven't yet installed Windows, so I assume no harm is done so far?
Did you mean not to install Windows itself on an external USB drive (hard drive, SSD, flash drive etc.), or did you mean not to create an installer of Windows on an external USB drive of some kind?

I mean do not install Windows from a USB installer. (macOS is another world, at least macOS won't write a Microsoft digitial cert into a Mac's BootROM. Also, Apple won't create a Mac that cannot understand a digital cert from Apple themselves).

1) Boot from CD -> default to install Windows in legacy mode.

2) Boot from USB flash drive -> default to install Windows in UEFI mode.

It may be virtually no difference to you. But "2" will cause BootROM corruption, which a normal user cannot fix / clear.

 

[macstatic]

I've continued the Windows installation part of the discussions here so as not to make this thread off topic.

Will, and the 7950 will display even not flashed.

So the 7950 is fully supported in MacOS 10.13? Is it also supported in earlier OSes?

 

[h9826790]

I've continued the Windows installation part of the discussions here so as not to make this thread off topic.



So the 7950 is fully supported in MacOS 10.13? Is it also supported in earlier OSes?

Depends on how you define "fully supported".

e.g. The audio part won't work natively (but can be activated by using AppleALC kext)

and there is no HWAccel support for the HD7950.

But apart from that, both compute / 3D acceleration have native support. Which should be the main function of the GPU.

 

[macstatic]

Depends on how you define "fully supported".
e.g. The audio part won't work natively (but can be activated by using AppleALC kext)
and there is no HWAccel support for the HD7950.
But apart from that, both compute / 3D acceleration have native support. Which should be the main function of the GPU.

Sorry, I was a bit unclear. Basically I just meant to ask if the HD-7950 works (displays on the screen) with MacOS 10.13, and also with earlier OSes. Or will it work with additional drivers installed with earlier OS version?
I noticed that when booting into OSX 10.6.8 (Snow Leopard) the screen was black, so obviously the card didn't work there.

About the 2nd fan that only spins up for a little while and stops again....
I found a thread entitled "Fan problem maybe?? Sapphire HD 7950 3GB GDDR5 Dual X with Boost" where several people say that it's not a malfunction, but the fan kicks in only when needed (high temperature). They're discussing the "Dual X with boost" model, but what interested me was the mention of the Vapor-X (emphasis in quotes below by me):

The only Sapphire Card that uses intelligent fan control to turn off UN-needed fans at idle is the Vapor-X which runs just one of its 3 fans at idle if you have the intelligent fan control switch enabled.

The card is fine it's just a power saving feature made by sapphire. If you want to turn it on, you can use AMD OverDrive, set the fans to manual, then max it out on 100% speed, see if it spins, if it doesn't then replace it

I really need to get hold of the user manual for this specific card version.
For instance, what is the "intelligent fan control switch" and where is it located, or is this something done in software?

 

[h9826790]

I really need to get hold of the user manual for this specific card version.
For instance, what is the "intelligent fan control switch" and where is it located, or is this something done in software?

From that description, there is no hardware switch for that, but software switch (in Windows) only.

Anyway, it's good to know that's normal. I wasn't awear this feature was used on HD7950 as well. Sorry about that.

If you flashed the card, then the HD7950 can display in 10.6.8, but just no acceleration.

 

[macstatic]

No problem. I hadn't heard of that feature either, but I really want to confirm it first (that the 2nd fan normally stays off until it's needed to cool down the card). I was directed to a Vapor-X R9 280X manual (post #966 in the "GPU compatibility list for cMP" thread), and I found several other similar GPU card manuals there as well, but none for my specific card and they're all very superficial (just listing up the various features, more like an advertisement than a manual). I need to find someone with the same card who has a manual, or perhaps an online review of this card will shed some light on the issue. The search goes on.....

There was mention of some Windows software in the Tom's hardware thread I mentioned in my previous posting which I'm not familiar with, so I'm going to try to find out more about that as well -perhaps giving me the ability to test and control both fans (from Windows).

If you flashed the card, then the HD7950 can display in 10.6.8, but just not acceleration.

Really? Wow, that's very cool and makes life so much easier
Does this mean that once I've flashed my Vapor X HD-7950 with the Mac EFI Boot screen I can boot into any MacOS version that my cMP can support (just like when I have my HD-5870 installed)?

I seem to recall some postings where I was told that if I buy a "Metal" GPU card I can use MacOS 10.14 (and perhaps beyond), but I lose the ability to boot into older MacOS versions (like I could do with my HD-5870). But from what you're saying they just forgot to add that this limitation only applies if you use PC "Metal" cards which have not been Mac-flashed yet.
So apart from being able to see which startup drives you can choose (when holding down ALT when booting) -which is very useful, you can also boot into other, older MacOS versions.

So in summary: once a (PC/Windows configured) "Metal" GPU has been reflashed for the Mac EFI boot screen you don't lose anything at all, and gain the ability to use a newer OS as well (10.14 and up)?

 

[h9826790]

I seem to recall some postings where I was told that if I buy a "Metal" GPU card I can use MacOS 10.14 (and perhaps beyond), but I lose the ability to boot into older MacOS versions (like I could do with my HD-5870). But from what you're saying they just forgot to add that this limitation only applies if you use PC "Metal" cards which have not been Mac-flashed yet.

Nothing related PC or Mac edition card.

I can boot 10.6.8 with my non fashed PC version Radeon VII. But same as your flash HD7950, only display, no acceleration.

What other people means, not you can't "boot" older OS, but "the GPU won't work as expected (mainly, no acceleration)" in older OS. Your HD7950 is the same, it support Metal, it can display in 10.6.8 after flashing, but no acceleration.