Game runs without a hitch and on nearly full ultra with an i5 4670k and gtx560 @1080p so it might be due to the crossfire setup as that can have issues with some games. Try disabling crossfire and then running the game as the cpu and single gpu should be enough.
I'm getting the exact same problems, with a similar hardware setup. I'm feeling pretty certain something in the code is screwy. None of my other games have ever done this. I can currently play anything else without issue, including Fallout 4. So, I'm kind of salty. x_x
