I have gtx 770, i5 4670k and 16gb ram at 64bit OS. Main menu and Armory works at 45/60+ fps (almost smoothly) as squad show case and caste run at 30 or below.
Still the potential is great. For me this lands somewhere between exanima and overgrowth (where exanima is my all time favourite and overgrowth is good but still meh) Not bad at all for an alpha preview!
Best regards to you!