Its not just Nvdia he needs.. my old PC had Geforce 6000 series card.. it was kinda pathetic on the sweet games like cysis, and it could run COD5 but it was so bliming laggy it wasnt worth playing(It had 2.0gb ram)It depends did your computer come with nvdia installed? If soo you shouldn't have any problems playing games on your computer.
Now I got dual GeForce 8800GTX cards it costs like £100-£150 ea mine came with my laptop. Thats what you need to get quality out of games.




