Crossfire and sudden 7950 proformance drop

Mlim666

Honorable
Dec 16, 2012
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10,680
I have recently been playing a large amount of Bioshock Infinite, recently I noticed that I was getting noticeably lower FPS (from the previous 60+ it changed to lows of 30). I ALWAYS play Bioshock Infinite with Crossfirex disabled as it is not needed.

After reinstalling drivers, reseating and disconnecting my GPU's I still have this problem. The fan has also started running on my second GPU even when Crossfire is disabled and I'm not playing a game. Before when Crossfire was disabled or enabled the fans on the second GPU would NEVER spin until I was in a game (with it enabled).

Yet now when I enable crossfire the fans do not spin when I'm in idle (not playing a game), which is what should happen, yet when disabled both GPU's fans spin.
 
I don't know about Bioshock Infinite performance, but the fan behavior is completely normal. In Crossfire configuration, the 2nd card is a slave, and powers down when not used. However, without Crossfire, it is a 2nd GPU to drive another monitor, bitcoin mine, or any other activity a program might use it for, which is why the fan spins.
 
Tearing can be resolved with v-sync, or if it is the microstutter issue, then use a FPS limiter. Check out RadeonPro, it might allow you to create profiles with Crossfire disabled for some games, and not for others. Nvidia's software lets you do that, there is a chance CCC has it (I don't recall it), but if it doesn't, RadeonPro might as well.