CPU (central processing unit)?

Just get the 2.66 Ghz intel Core i7, most games won't even come close to maxing out the processor. You can probably run call of duty 4 without using even 25% of the processor. But you should be more concerned about the graphics card because those games don't rely too much on CPU. The GTX 285 is a really nice card, especially with the physX update (although you won't need the GPUs processing power if you use a good processor).