I dont know if this has been posted already but here's a tip on how you can boost performance, edit the Doomconfig.cfg file with notepad, and goto the line that says Seta_image_cachemegs "32" there maybe a diiferent number her but it's usually 32

change the number depending on how much ram you have, ie if you have 512mb change to around 64 or 128 if you have more have a higher number, save the file and run you should see a boost in frame rate and also be able to run in a higher res or run in even more detail just play around and see what you can get, this should give a boost to any system playing doom3.

old news but thanks anyway! there's a tweak tool out there to automate performance tweaks for doom 3 aswell if anybody is interested....

otherwise, doom3? huh? you mean half life 2....