How many GPUs can Windows 7 Support?

[tachi641]

Hi Folks,

I was wondering, if there is a difference for mining with Windows 7 32bit, or 64bit.

Also, I was wondering if windows can run up to 7 Cards, I have a MSI 890FXA - there are 7 slots I can fill up with vid cards, would windows be able to detect them all?

[Elios]

as many as you can cram on the motherboard

[1.21gigawatts]

windows can only run 4 GPUs

[Genrobo]

I'm going with 4 on this one.
Though I have yet to see a source or citation to back it up.
People running multi-card rigs seem to keep running into issues with Windows + multiple cards.

[bcpokey]

windows can only run 4 GPUs

I'm still waiting for proof of this claim I've seen multiple times.

For example: http://www.techpowerup.com/forums/showthread.php?t=100993 is a 6 gpu setup running under windows. 3 physical cards, 6 physical cores.

http://www.maximumpc.com/forums/viewtopic.php?p=931366#931366

This fellow is running 4 dual core cards, again 4 physical cards, 8 physical cores.

http://hardforum.com/showthread.php?t=1492462 suggests that 8 physical GPUs is the limit, but no real sources are cited.

Some time if I get a bigger PSU and some pCI-E extenders I may solve the mystery for myself, but for now I rely on someone else to answer conclusively.

[1.21gigawatts]

easiest way to test is to load windows onto a machine with 3-6990s.  I'm sure someone has a rig with 3-6990s that can verify this?

[DeiBellum]

From what I have seen from the blogs online, it can only support 4 GPUs, while X11 can support up to 8 before it Segfaults.

Source: http://blog.zorinaq.com/?e=46

[tachi641]

I have 3 card right now and it's running fine, I'm headed over to a PC shop to pick up some cables then I'll be at 4... I'll test it out to see if I can do more, I'll update you guys.

[Vwlopez3]

I plugged in 5 5870 cards into MSI 790-fx it saw the card and installed the driver but phoenix rising could'nt run the 5 card and gpu-z continued to say there was an error. So i think 4 is the limit but would love to know of a workaround so i could use my 890fxa gd-70 also

[tachi641]

So folks, I am running into a new problem.

I tried to plug in my 4th card, however, my mobo won't boot up.

I am using a 1000W Kingwin PSU

Currently it is running

2 x 6950
1 x 5850

the 4th card would be another 5850

Do you guys think that's not enough juice to run it?

[mrb]

I'm still waiting for proof of this claim I've seen multiple times.
For example: http://www.techpowerup.com/forums/showthread.php?t=100993 is a 6 gpu setup running under windows. 3 physical cards, 6 physical cores.

The 4-GPU Windows limit applies to AMD GPUs, not Nvidia.

You will find plenty of examples of people running 8 Nvidia GPUs on Windows (such as your link), but never AMD. I myself tried 4 x HD 5970 in Windows 7 64-bit with Catalyst 10.12, but I could never get any CAL app to use all 8 GPUs.

[tachi641]

I'm still waiting for proof of this claim I've seen multiple times.
For example: http://www.techpowerup.com/forums/showthread.php?t=100993 is a 6 gpu setup running under windows. 3 physical cards, 6 physical cores.

The 4-GPU Windows limit applies to AMD GPUs, not Nvidia.

You will find plenty of examples of people running 8 Nvidia GPUs on Windows (such as your link), but never AMD. I myself tried 4 x HD 5970 in Windows 7 64-bit with Catalyst 10.12, but I could never get any CAL app to use all 8 GPUs.

Mr B.

Do you know if I am having power issues with my setup?

[mrb]

Link to the detailed specs of your exact model of PSU. There are multiple Kingwin 1kW.

[gigabytecoin]

4

[tachi641]

I'm still waiting for proof of this claim I've seen multiple times.
For example: http://www.techpowerup.com/forums/showthread.php?t=100993 is a 6 gpu setup running under windows. 3 physical cards, 6 physical cores.

The 4-GPU Windows limit applies to AMD GPUs, not Nvidia.

You will find plenty of examples of people running 8 Nvidia GPUs on Windows (such as your link), but never AMD. I myself tried 4 x HD 5970 in Windows 7 64-bit with Catalyst 10.12, but I could never get any CAL app to use all 8 GPUs.

Mr B.

Do you know if I am having power issues with my setup?

Hi MrB!

here it is

http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4256917

[mrb]

This PSU can handle 2x6950 & 2x5850, assuming you don't have insane overclocks, or other hardware in this machine that is very power hungry. The PSU claims to support 80A on the combined 12V rails, whereas the GPUs need only 59A @ 12V, leaving 21A (252W) for the rest of the system.

[Genrobo]

This PSU can handle 2x6950 & 2x5850, assuming you don't have insane overclocks, or other hardware in this machine that is very power hungry. The PSU claims to support 80A on the combined 12V rails, whereas the GPUs need only 59A @ 12V, leaving 21A (252W) for the rest of the system.

dohoho
I think there's something wrong with your calculations, but you're still probably right.

[BTCBuyer]

This PSU can handle 2x6950 & 2x5850, assuming you don't have insane overclocks, or other hardware in this machine that is very power hungry. The PSU claims to support 80A on the combined 12V rails, whereas the GPUs need only 59A @ 12V, leaving 21A (252W) for the rest of the system.

I am having the exact problem as the OP.

Our systems seems identical from his description, awkwardly enough even our power supplies are the same, however my system will boot up with all 4 cards.

OP, I suggest you double check your Molex to PCIe converters. I know that the ones that comes with the video cards will have a double brown wire and only 5 slots filled out instead of 6. I had to buy some from a computer store and rewire it myself in order for my 4th card to boot up. I think you might have the same problem.

Now that I have that solved.

The main problem I have is that GUI won't boot up when I have all 4 cards in. Windows will detect all 4, in device manager will have all 4 showing. Catalyst will have all 4 showing. But GUI won't boot up. Anyone know of the solution for this?

[namley]

I was under the assumption Windows 7 (x86/64) could only address 8 GPU Cores, Same with Ubuntu.
Solaris I heard was some astronomical amount.

[Genrobo]

I was under the assumption Windows 7 (x86/64) could only address 8 GPU Cores, Same with Ubuntu.
Solaris I heard was some astronomical amount.

>mfw Solaris + GPU