Team Fortress 2 Performance Tweak Guide
 

Over two years since its original release, with the coming of HL2: Episode 2, I've completed a major revision of the Half Life 2 & Source Engine Tweak Guide. The guide is now fully up to date with the latest build of the Source Engine; I've retested and documented a range of existing and new settings, including several new advanced tweaks, and even updated all the screenshot comparisons. Give it a read through if you run any Source-based game.

http://www.tweakguides.com/HL2_1.html