I tried to boost fan speeds as slughead adviced but it didn't helped at all. Most difficult is the problem after i have booted my mac, pressed alt button and then i choose to boot with windows. Screen just go black after that and nothing happens. I tried to install my windows again with 2 cards but installation also didn't worked when it was supposed to go to windows first time. So i don't hear any windows sounds, screen just stays black and nothing happens after i put my second card in my mac pro. With osx everything works just fine.
Hey, I just recreated your issue.
Try this for me, flip the BIOS switch to just PC BIOS on BOTH cards. (reference 7970 and 7950 have these, even the Mac Sapphire one has it, later boards do not)
Let me know how it goes.
Not working... Same result with every catalyst versions... I tried also to flash my xfx 7970 card bios from my "mac edition" 7970 pc switch bios. But after that xfx card started to spinning fans with terrible speed and it doesn't boot at all. Any suggestions how i can do bios recovery for that card or do i have to do it with pc? And yes i took copy from xfx original bios before flashing... Now i know how to flash ati cards and i also know what happens when i put the wrong rom in it What do you think macvidcards, would it be vice idea to try to flash "mac edition" 7970 pc switch bios from same bios what xfx card have? I have now tried to do everything but it just doesn't work. Power shouldn't be the problem. I have external 520 w seasonic power supply wish i bought from you so i think it's enough for this crossfire configuration?