Quake 4 Tweak Guide
 

Despite the fact that tweaking Quake 4 is extremely similar to tweaking Doom 3, and after some delays, I decided that given the large fan base for the game, it deserved a tweak guide of its own. This Quake 4 Tweak Guide covers all the in-game settings in detail, including screenshot comparisons of image quality differences, and contains a wealth of links to important Quake 4 resources. The guide is rounded out with advanced tweaks which have been tested and work on Quake 4, since some of the Doom 3 commands are different for this game. All in all, the guide is a central resource for Quake fans and should help new and experienced Quakers alike.

http://www.tweakguides.com/Quake4_1.html