I don't know why people keep saying COD4 runs better. I have an A64 3000+ 1 gig of ram and an 8800GT and COD4 is so processor limited that it is unplayable for me even on low settings. Crysis I can play at 12x10 on Medium/High and I get 20-40fps avg (depending on the area and settings). I could even play it with the same system except with an x800xt and it ran fine on low. Only problem Crysis has for me is with alot of physics going on, eg blowing up a building. That's not even to mention how much more is going on on the screen in Crysis than COD4.

Also, I remember reading something from Crytek awhile back saying how they have optimized the engine for Multiple cores and I think 64-bit (not sure on that one). Along with some other improvements I was impressed by. Hopefully they'll be using that version of the engine for this next game. I for one am looking forward to this.