My Crossfiring of 7970 runs really bad. Help

Hi all.

It has been two days that I have been trying to crossfire my 2 7970 and it just doesn't work. Now I am at a point where I have completely uninstalled all AMD stuff, ran Ccleaner and Driver Seeeper. I then reinstalled Catalyst 12.4 and enabled crossfire. When I run in Skyrim, Alan Wake and Hard Reset I get half the FPS or WORSE than on each 7970 alone. I check FPS with FRAPS. I had GPUZ running ok with CAT 12.3 but now it craches my pc when I try to read info on second video card. I disabled ulps. I had 2 entries, set them to 0. For Skyrim on single card i get 45fps with eveything set to max. Alan Wake is the same thing. Also the same with Hard Reset. I read a Guru3d 7970 crossfire review and they show benchmarks that Skyrim and Hard Reset scale at almost 100%. All my tests are at 2560x1600.

I tried with one and 2 crossfire bridges connected and I get the same results. And I have the 8pin and 6 pin connectors on each GPU connected to the PSU. And I tried both PCIE Power Supply locations on my PSU when I did the single card tests so I am pretty confident that my PSU is running ok and should be able to drive 2 GPUs. I am really stumped now. Any help would be appricated.

Here are my specs:
CPU: I7 2600K @ Stock 3.4 Ghz (for now)
MB: ASUS P9Z68-V Pro Gen 3
GPU: 2 x Saphhire Refence Radeon HD 7970 3TB
RAM: 16GB 4x4GB G
PSU: XFX Pro Series 1000W Platinum

vipernig said:

Hi all.

It has been two days that I have been trying to crossfire my 2 7970 and it just doesn't work. Now I am at a point where I have completely uninstalled all AMD stuff, ran Ccleaner and Driver Seeeper. I then reinstalled Catalyst 12.4 and enabled crossfire. When I run in Skyrim, Alan Wake and Hard Reset I get half the FPS or WORSE than on each 7970 alone. I check FPS with FRAPS. I had GPUZ running ok with CAT 12.3 but now it craches my pc when I try to read info on second video card. I disabled ulps. I had 2 entries, set them to 0. For Skyrim on single card i get 45fps with eveything set to max. Alan Wake is the same thing. Also the same with Hard Reset. I read a Guru3d 7970 crossfire review and they show benchmarks that Skyrim and Hard Reset scale at almost 100%. All my tests are at 2560x1600.

I tried with one and 2 crossfire bridges connected and I get the same results. And I have the 8pin and 6 pin connectors on each GPU connected to the PSU. And I tried both PCIE Power Supply locations on my PSU when I did the single card tests so I am pretty confident that my PSU is running ok and should be able to drive 2 GPUs. I am really stumped now. Any help would be appricated.

Here are my specs:
CPU: I7 2600K @ Stock 3.4 Ghz (for now)
MB: ASUS P9Z68-V Pro Gen 3
GPU: 2 x Saphhire Refence Radeon HD 7970 3TB
RAM: 16GB 4x4GB G
PSU: XFX Pro Series 1000W Platinum

Click to expand...

Could be microstuttering? Google it; its a well known issue with multi-gpu setups. I just set up xfire 6950s, and while it's not terrible, it's definitely noticeable.

Alright I made I little discovery in my case. I was reading on other crossfire problem threads and I did not try to to test each card on the second pci slot. So for the Asus P8Z68-V Pro GEN3, the top PCIe in blue is rated PCIe 3.0/2.0 x16 for single or or dual at x8/x8. The second gray PCIe is rated PCIe3.0/2.0 at x8. Now having a i7-2600k I can only use PCIe 2.0. So I procedeed to test both cards on the gray PCIe X8 mode and to my surprise they performed SIGNIFICANTLY better. In the scenes where I was averaging 45fps in Skyrim I now average 55fps. This is a MASSIVE difference. I went to benchmark in Hard Reset and I get an Average of 100fps. And Alanwake is also on average 10fps more. This is a HUGE difference and this leads me to believe that there is an issue with the PCIe interface.

Does this mean I have a faulty motherboard? I checked my asus drivers and they are up to date. What do you guys think? I am off to bed. Atleast now I am performing like those benchmarks I read for a single HD7970.

As for micro stuttering this is not what I am experiencing. I read up on it and looked at benchmarks and the worst FPS was that of a a single card and the best fps was double what a single card was delivering and then it fluctuated between both values which is not what I experience when I crossfire. I get a constant worse FPS than a single card. And I would say with the new FPS that I gathering from running on the second PCIe slot, they are literary half or WORSE the FPS that I get from my single card.

So back to the question. Faulty MB or PSU(doutfull it is a XFX PRO 1000W Platinum, which is the same as a the Seasonic 1000W Platinum. Or is there something I am missing?

Crossfire doesnt seem to work very well with the 12.4 drivers with the 7970

I had to disable ulps to get crossfire to work properly (in 12.4).

Go back to 12.3 and you will notice that your second card is not stuck in Idle clock mode, or stuck in PCIE 1.0.

But with the advent of 12.4 problems arise. I reported my issue, report yours if 12.3 works fine.

Never mind i see you were using 12.3 earlier...
BUT i can verify that my two crossfire'd 7970 cards worked fine in 12.3 but not in 12.4 (without ulps disabled)