HD7950 OC Edition Crossfire won't function

[Millseboy]

Ok, I spent my last friday building my new rig:

MB: ASUS P8Z77-v Pro
CPU: i5 2500 with Antec Kühler H2O 620 installed
HDD: new 2TB Western Digital and 1TB Western Digital from my old pc
Memory: 16GB Corsair Vengeance 2133Mhz
GPU: 2× HD7950 OC Edition (Core clocked at 950Mhz) 3GB DDR5 VRAM
PSU: TX850W Corsair (850 Watt)
Windows 7 Ultimate

So, me all happy started the computer and installed windows. Nothing wrong yet, system running from the integrated graphics from the CPU. Then I installed the latest ATI drivers (12.6) and the trouble began: computer would freeze at the end of the "Loading Windows" screen. Safe mode would boot fine, tried multiple things and then took out one card. Eureka! It booted. So I uninstalled the drivers and did a driver sweep, then installed them again (while only one card was in the PC), shut windows down and put the second card in. It worked: now windows will boot.

But not so long after that, a new problem came crashing in: When crossfire is enabled and my GPU is being stressed, (Battlefield 3, Furmark, Skyrim) black or colored lines start appearing over the screen. Like when v-sync is disabled, but now instead of normal screentearing, I get those big colored or black bars flickering over the screen. This happens only for a few seconds, then the sound will hang and the PC will crash. Resulting in a reboot or a BSOD. (0x0000007e SYSTEM THREAD EXCEPTION NOT HANDLED -- and then something about atikmdag.sys)

First I thought my cards were broken, but then I remembered the problems I had with crossfire. So I started up battlefield 3, waiting for these artifacts to appear and at the moment it happened, I pressed ctrl+alt+delete. Battlefield 3 didn't minimize, but started running in windowed mode and the lines were gone. I could do everything on my desktop, but when I enabled full screen again, I got the lines back and it crashed just a few seconds after that.
I read somewhere that crossfire only works in full screen, so I'm guessing that that's the culprit. But how do I fix this? Have tried multiple drivers and also switched the cards. Nothing works. Is one of the cards broken or is the system screwing up?

 

[Millseboy]

Another BSOD, during FurMark this time: 0x0...03b: ntoskrnl.exe and atikmdag. Tried disabling ULPS, obviously didn't work!

 

[rdc85]

-Is the card crash if cfx is off or single card is used?
-did u install the application profile from amd?
-have u tried catalisyt 12.4 or 12.7?

If it crash in single mode/card, it mostly hardware problems
IF u don't install app please install app, if the previous driver or beta driver works then it driver problems....

btw Sometimes cfx is picky if card being O.C -ed (even it was factory O.C)

edit:
Do not know if SLI is picky too. I never tried SLI, so no experience about it (just to be fair for both green and red teams)

 

[Millseboy]

Thanks for the reply The system crashes ONLY with cfx, I did install the CAP and I've tried many of the catalyst versions, no luck.

Instead of the HD7950 CF, I've now put my old GTX295 in the pc and everything is working fine in SLI mode.

I'm seriously thinking about returning these cards and going for nVidia... unless this can be solved of coarse.

 

[rdc85]

In my case my card doesn't like O.C. in CFX mode even they are twin and same batch production....

Even increased 1 Mhz will cause an artifact (If it single both of them can increase up to 50 Mhz with no problems)

So this maybe the same case, if it's me I would tried to use after burner and try to downclock to ref card speed and test it.. (if it fine then i will demand refund since they made non stable O.C. card )

 

[Millseboy]

Hmm keeps crashing. Getting kinda desperate now...
What could it be...? I really want this to work of coarse...

 

[Millseboy]

Crossfire is just picky, or the drivers are crappy... don´t know.
After around with the pc for three full days (seriously, from ten till twelve all three days) and finding out that my ´old´ GTX295 works just fine, which is practically SLI in one card, I concluded that the problem lies with crossfire and the drivers.

Anyway, had more than enough of all the trouble and my holiday-job is paying better than I suspected, so I´m going to return the HD7950´s and I´m getting a GTX690.

Still: rdc85, thanks for the help.

 

[DoP3DoG]

Hi there,
I also have two HD7950's crossfire and have the same issue. Does anyone has a proper solution for this already?

 

[iam2thecrowe]

Hi there,
I also have two HD7950's crossfire and have the same issue. Does anyone has a proper solution for this already?

Don't overclock. or, sell the cards and get a better single card. crossfire just introduces problems, and doesn't give that much of a perceivable performance increase once the frames (or lack of frames) reaches your monitor anyway.

 

[DoP3DoG]

Hi there,
I also have two HD7950's crossfire and have the same issue. Does anyone has a proper solution for this already?

Don't overclock. or, sell the cards and get a better single card. crossfire just introduces problems, and doesn't give that much of a perceivable performance increase once the frames (or lack of frames) reaches your monitor anyway.

Thanks, so besides the bad performance of crossfire there is no remedy for the issue?