adding more ram is better?

how much affect does this have...i just upgraded my pc to a dual core 2 processor 2.13 ghz 2 gig ram 3 hds 250 gigs each 7600 256 mb sli...i have space for 2 gig ram im going to get another gig ram this week will this make my pc even run faster?

It will enhance gaming performance and stuff like that. But it shouldn't make your PC run faster in just regular use. If you feel like 2 gigs is enough, make sure you lower the page file size(you can even turn it off if you have enough RAM, I find 2 gigs is about the size I use for gaming). That will greatly increase performance.

But as I said, more RAM won't give you any speed increase, it just lessens the capacity of the RAM as a bottleneck in memory intensive programs.

Performance is about what you do with your computer.. You can play solitaire with 32MB of RAM too and it's still blindingly fast

If you can't tell whether 2 gigs of RAM is enough or not for you, then most likely you are not doing anything with your computr that would require more.