I've been compelled to play a lot of MWO, MechWarrior Online, and I've noticed that it will periodically crash during my gameplay if I have crossfire enabled. Sometimes these crashes are only the AMD display driver (leading to a playable game with no visuals until the driver restarts) but other times it crashes so hard that the only recourse is to restart the computer as even the Num Lock key does nothing. I also notice that if I have crossfire off my framerate actually improves. That said, this game runs entirely on DX9 and on the Crytek engine and I only get 50-90 FPS @ 1080 with either 6870 standalone or in crossfire. That doesn't seem right to me at all as other, better looking, DX9 games I play (eg: Borderlands 2) pull in much higher FPS.
Has anyone else encountered this?