Are you running AMD or Nvidia drivers? I'm running Nvidia with GTX 670 and absolutely no problems. In fact, I've never even seen the game crash before.

However, if you're running AMD drivers, I won't be surprised you're having crashing issues, especially since you're going Crossfire. AMD always have issues with new games and their drivers are known to bug with new games ALL THE TIME (I had the AMD 6950 Crossfire & 7970 before). On top of that Crossfire bugs out on so many titles it's almost ridiculous on AMD's part. It's got to the point where I only trust single-GPU solutions now, which is why I'm running a single Nvidia 670, and had no problems anymore, in any game, ever.

I can almost guarantee everyone here in this thread has an AMD card and driver.