Maximus V Extreme not recognizing multiple GPUs

[bitpaul]

I am having an issue where by my Maximus V Extreme motherboard will not recognize multiple GPUs. The motherboard was just purchased an open box item from NewEgg.com so to my knowledge the board never worked. At the present time the only slot that will recognize a video card is slot #1. Per the manual if I am going to add multiple cards I should add them as follows:

1 card - slot 1
2 cards - slot 1 & slot 2B
3 cards - slot 1 & 2A & 3
4 cards - slot 1 & 2A & 3 & 4

I have tried all of the above configurations as well as one card in each of the slots by itself. The only configuration that works is a single card in slot one. Each of the GPUs have been tested by themselves and in multiples using other known to be good motherboards. To accommodate multiple cards I am using pci-e risers that are known to be good.

Video Cards:
4x - XFX 7970 - 925Mhz

BIOS Information:
Bios Version: 1903 x64 - latest bios
Build Date: 08/19/2013

PSU:
1000w Cooler Master - no reason to assume it is a power issue

Resolution Attempts:
1.) Updated bios to the most recent version which is listed above
2.) Flipped the PCI-e toggle switches back and forth multiple times to insure they were indeed in the "on" position
3.) Cleared the CMOS
4.) Attempted a single GPU in every slot - only slot 1 will recognize a card
5.) From the bios pressed F5 to reset "Optimized Defaults"
6.) Bios > Advanced > System Agent Configuration > NB PCIe Configuration - toggled FORCE_PCIE1_X16X
7.) Bios > Advanced > System Agent Configuration > NB PCIe Configuration - toggled Auto, Gen 1, Gen 2 on each slot
8.) Bios > Advanced > System Agent Configuration > NB PCIe Configuration - toggled Gen3 Present options
9.) Disabled on board components (wifi, bluetooth, sound card) to resolve the potential for IRQ issues.
10.) I do not have any known GPU pci-e cards to try.

Any ideas would be much appreciated!

[Nate152]

Hi bitpaul, welcome to the ROG forums, the best place on the internet to find help with pc gaming. I think a 1000 watt psu is weak for 4 7970's. One 7970 requires a 500 watt power supply. Does it have four 6-pin and four 8-pin pci express power connectors? Anyway I think I see the problem it is the NB PCIe Configuration - toggled FORCE_PCIE1_X16X. When I set that to enabled it only recognized 1 of my 3 cards too. let me go look to see what that is set to and I will post back.

[Nate152]

OK, go to BIOS, Advanced Tab, System Agent Configuration, NB PCIe Configuration, at the bottom FORCE PCIE X16 set that to disabled. That should let all your cards be recognized now. Post back and let me know.

[bitpaul]

Update - just chatted with online tech support. The board requires RMA. Boo! I was really hoping that I didn't do that good of job troubleshooting this issue. But thank you for all the posts here, all very helpful!

[bitpaul]

Hi Nate, thank you for the welcome and super quick response. Toggling that option had no effect.

[bitpaul]

I have a 1300w Lightning I can try as well.

However, as part of troubleshooting I was attempting to just get 2 cards working at the same time. Never got to the part where I was maxing anything out. But I will keep that in mind once I get the board back from service if I have an issue adding more cards and it seems to be power related.

[Nate152]

I'm sorry to hear that had no effect on getting your GPU's recognized by your mother board. Good luck with your RMA, I hope it is a speedy one for you. I would feel much better about a 1300 watt psu powering quad 7970's. I think you are still going to be pushing it, especially if you plan on doing any overclocking.

[Nate152]

Hey bitpaul, I was bored so I was surfing around the internet to see how much power quad 7970's draw. It is not as bad as I was thinking it was. In fact I'm quite impressed. http://www.hardwareheaven.com/reviews/1376/pg1/sapphire-radeon-7970-quad-crossfire-first-look-perfor... I would still use that 1300 watt Lightening though.

[HiVizMan]

Two cards will run just fine with a good 850+ PSU.

[revenge666]

i have 2 XFX 7970 black edition with maximus V extreme my psu is Thermaltake TRX 2 1000W and works perfect and never had a power issue.