So I bought a Wind -force 6850 to accompany my Sapphire 6850. Despite what everybody says about the 6850s being the worst cards to crossfire I put it in my pc , installed new profiles and enabled crossfire and launched Bf3. The maps loaded up faster and i was in the gun load out screen with 80fps on high get in the game and it drops to 40 and then goes back up to 60. Put it on ultra with 4xAA(I know Bf3 takes 2gb of Vram @1080p ) it almost crashed. Set it back down to 2xAA and it ran well BUT it started to lock up and stutter . So I did some tests on Fur Mark. Got amazing scores (over 4000) my temps on the top card are @90C and my bottom ran 15 degrees cooler. Went to the Unigine benchmark and got over 60fps with 4xaa and the highest settings. So went to play Saints Row three only to get 30-40 fps( I got that with one card ). I Played BBC2 and got negative scaling. Whats going on? Is it the fact that i'm running a 16x/4x config or is my cpu bottle necking the two cards? Should i sell these cards or should i figure out a way for them to work?Should i switch the cards and have the cooler one on the top?Do i have to make sure that all of the cards clocks are the same? Any Help would be much obliged
Drivers: Catalyst 12.6
All motherboard Drivers are up to date
16/4 isn't optimal, not sure how much a 4x would hold back a 6850 but still. As for the temps, is there room between the cards? Do you have good case airflow - that's really important when you put more heat-generating components in there.
You could try swapping the cards, but if they both have decent coolers odds are the temps will just swap so the new top card is running hot.
CPU bottlenecking shouldn't cause negative crossfire scaling, but of course it could cause disappointing performance otherwise.
I Have a Coolermaster Cm storm with two 120mm pointed directly at the cards. There is a lot of room between the cards. The Sapphire has a Reference like cooler. The Gigabyte runs 10-15% cooler overall. It is also quiet hot in my room atm and the only fan that is pushing hot air out is the big 200mm on the top.