System Performace Tweaking?

A not-so Anonymous Coward asks: "After being on a rather slow PC for some time now, I have finally made the jump to a 1GHz+ PC. Being fairly new at having a rather fast PC, I am not very sure where to go for system performance tweaking. A few friends pointed me to Monroe World and TweakXP. Both are pretty good sites, however I find that my system still doesn't perform as well as it should when running a benchmarking test like 3dMark 2003. My score is just under 2000. I know people who have slower systems than mine and get a score around 5000. So I am turning to the Slashdot community to ask: Where do you go to find out the latest and greatest hardware and system tweaks? Do you have your own tweaks, and if you do would you mind sharing your secret tweaking tips?"