Yeah dude, biggest one people tell me is either drivers or that it's just AMD cards. I've tried to also reinstall my entire OS, tried multiple drivers, I have liquid cooling so no overheating for sure. It's just this game, it needs major optimizing.
My current setup:
980x Extreme CPU (Overclocked to 4.0 GHZ)
24 gb DDR 3 ram
Radeon 7990 AND 7970 in tri crossfire with liquid cooling
Window 7 Ultimate 64bit
The most annoying thing about all of this, is during phase 3 I had absolutely no problems, during phase 4 just a few, and on release it's constant. And I don't know how your FPS is in game vs benchmark, but the benchmark told me I'd be getting 70+ FPS easy. I get about 25-35 average. :/ So yeah... they REALLY need to optimize and fix this stuff, and then I'll be super happy.

Well me, and thousands of other people.