Doom 3: CATALYST 4.9 BETA

ATI has released BETA Catalyst drivers with OpenGL improvements specifically for DOOM 3. The drivers are unsupported, and while I'm downloading them now, I can't vouch for any performance improvements.

Update: Having just installed the new driver, I can say that performance is indeed improved. Doom 3 will now detect and set the game at higher settings that it did before. Another little tip for those with lots of RAM is to change the image cache setting in the CFG file to use more memory.