help a semi noob

[kosta104]

I was wondering what can i do my system to make it perform better? Everything right now is at the stock setting. this is what i have:
AMD athalon 3800+ dual core 64 bit (socket 939) cooled by a Thermaltake CL-P0310 120mm CPU Cooling Fan

Gigabyte GA-K8N Pro-SLI mother board

four 2x512 dual channel corsair xms memory total of 2 gigs

for video im running SLI evga 7800gt co

sound i have the creative xfi fatality extremegamer

i have two western digital sataII 120gig hard drives

And for dvdrw/cdrw i have a plextor ( a newer one i forget the model)

All this is rapped up in a antec p180 case with a antec true power trio i think its the 600w or 550... i forget but it is SLI rated.