I haven't tried MP but from anywhere between 20 mins to an hour of playing SP the game will freeze and the screen will then turn black requiring a hard reset of my computer. This doesn't seem to happen when only a single GPU is in use.

I've installed 13.2 beta 7 which was supposed to fix this but it still happens. My specs:

AMD FX-8350
Crosshair V
AMD 6990+6970 trifire

Has anybody else have this problem? Would rolling back to maybe 12.11 or 13.1 help?

I'd just play with 1 GPU but the game doesn't run all that great with just 1. I kind of need Crossfire to work else I'll have to turn stuff down quite a bit and I'd rather not