hey, im new to all this stuff....but im really into PC gaming and wanna play all the newest games (im playing far cry now!

)....
could any of you tell me if there is any way XP can be tweaked for better performance in games? thanks!
and i know this is the OS section of the forum, but does any1 know any other things i can tweak for better in game performance?
here's my system :
2.53GHz P4 (widows XP Home)
512MB RAM
Radeon 9800Pro
SB Audigy LS
80GB HDD
thanks!