Playing on Win7 64-bit w/ an unoverclocked AMD 1090T. Last I checked, when the game runs only about 30% of my processor's power is being used (during open beta, too tired to load up the game right now). Sort of 2.5 cores used I suppose. The game is more of a GPU hog than CPU. So may run well on 2 cores, but I would aim for at least 4, but 6 like what I have feels wasted in everything but compressing files.