Improve your DOOM3 performance.
There are a couple of things you can do that improve performance,
Goto the \Program Files\Doom3\base\doomconfig
open it with notepad, then scroll to
seta image_cacheMegs "32(or 20)"
Change it to 96, 128, 256 w/e just make sure you have double the ram of the number you put.
Go into the \program Files\doom3\base directory. Use winrar to unpack the pak000 pak001 pak002 pak003 pak004 files into the program Files\doom3\base directory. then MOVE the pak000 pak001 pak002 pak003 pak004 files to somewhere else on your hd (they are needed for network games and can be copied back later if needed)
Now doom3 will not have to unpack files while your playing, it makes a HUGE difference.
With this i've got my doom3 running in ultra mode at 1280 x 1024 at 72.3fps!
Intel Core2Duo 6400 @ 3.4Ghz
4GB Geil 6400 Ultra
3 x 500 Gb Samsung HD
EVGA 8800 Ultra OC