Problems with XFX 6870 Crossfire

Well I have been having an ongoing problems with my dual XFX 6870s in a crossfire situation that I can't seem to figure out how to fix. Sometimes, at completely random times, the fans of my graphics cards turn all the way up to 100% and then shortly after my computer screen goes black.

At first I assumed it was the drivers, so I uninstalled + driver sweeped my drivers and then downloaded ccc 10. This worked for about a week then the problem started happening again. I moved back to ccc 11 and again it continued to happen.

After I realized that uninstalling/reinstalling the drivers wasn't going to work I decided to try flashing the card bios's. So I individually flashed each card's bios to some Asus BIOS which didn't seem to help very much at all.

At this point I realized that I had no other choice but to reinstall windows. So I backed up my data, formatted all of my disks, and reinstalled windows on a different hard drive. This worked very well for the past ~2 weeks. Today for the first time I turned on Crossfire and began reinstalling all of my games and about an hour ago the fans again went up to 100% and black screened.

Individually, each card works fine. I have used both cards and neither seem to have any issues working individually, however once I turn on crossfire a crash is imminent. I also have changed crossfire bridges. One other side effect I noticed is that on my non primary card catalyst control center is never able to tell me the current fan speed or temperature. The fan speed stays at 20% no matter what I do and the temperature stays at 0 degrees.

Is there anyone who has had a similar problem that would be able to help me out or help me to discover my problem? Any assistance would be very much appreciated in this extremely frustrating matter.

Update: Now suddenly catalyst control center doesn't even recognize the other card. It thinks that I am only using one card for some reason. It is also getting even worse, sometimes the fans start blowing and the screen goes black immediately upon turning on the computer. This is growing even more frustrating. :(
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  1. What PSU do you have? Could be a power issue.
  2. I have the OCZ Gamexstream 850w model. I should have enough power, though I know OCZ is not the best PSU manufacturer.
  3. while messing around with graphics card configurations I may have discovered the real root to all of these issues.

    Whenever I have the graphics card not in the first PCI-E slot, the card will not always display anything. It took me several restarts to get something to display and on one of the restarts even though I only had one card in, the card's fan went up to 100%. It is now working fine for now in the third slot, but I am unsure how long this will last. So this led me to believe that the real problem was not in the fact that I am using multiple cards but in the fact that I have a card in another PCI-E slot.

    I experienced the same problems with both cards in both the second and third PCI-E slots. I am unable to fit the card in the fourth PCI-E slot otherwise I would test that also.

    So do you think it is a problem with my motherboard now? Or is it a problem with the way my power supply is giving the other PCI-E slots power? Thank you in advance for your assistance.

    Edit: I am using the Gigabyte GA-X58A-UD3R rev 2.0 motherboard w/ an i7 950 CPU by the way if this helps.
  4. When in crossfire, the cards are close together limiting circulation and can cause the cards to overheat. When they get hot enough, the fans will keep increasing to 100%. The part that seems to overheat first on these newer Radeons are the VRM's, which regulate the voltages for the VRAM.

    You might try underclocking the VRAM, which will lower the temps of the VRM's and VRAM making this less likely to happen. The GPU could also be overheating.

    Another thing to check, which happens to me a lot, is your air flow. I have these screens on the intake fans going into my antec 902 case. Those get dirty every couple weeks. When they get dirty, my air flow goes to crap and things get hotter inside. Perhaps you just need to clean out your case to make sure there is good air flow.

    The type of issue you are happening is common for overheating.
  5. I have an extremely similar problem, with crossfiring MSI 6870s on a Crosshair IV Formula board.

    I am struggling so hard to find a solution.

    I can effectively eliminate PSU and airflow/cooling as causes: Corsair AX1200, and a Lian Li case with a MILLION fans - everything runs very cool.

    Any ideas anyone?

  6. Well bystander may have something up there but if its drivers related....

    all I can say is that I abandoned 6870 crossfire for absolutely putrid drivers, my problems were consistent across several drivers and I was fed up so I sold them, AMD treats the midrange crossfire customer as a minority, good luck
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