Dark Comet said:
He does not have 4GB RAM, only 2GB. The best upgrade you could do for FPS is the graphics card. But you need to make sure you have a good PSU too. Getting a 64bit OS and upgrading to 4GB RAM would be a good idea. Most gamers aim for at least 4GB these days.
Whoops, I was answering multiple threads at a time.
What you said is true, getting a better GPU can make a big difference in the frame rates. And for that he needs good PSU. I am assuming he has a 400 or 450 W PSU, since he already has a GTS 250.