I have the same basic problem...dual boot win2k and Redhat 9.
In windows quake3, i get 135 fps in demo four, in linux with 24 bit desktop i get 64-65 fps. I read through this thread and changed to 16 bit and got my fps up to 100 fps. Any ideas how I can get the performance up close to windows so i can play enemy territory in linux? Hardware is as follows:
Athlon 2000+ XP
512 MB ram
Geforce 4 MX 420 (junky, but I at least want close to the same performance as in win2k)
Fast writes enabled, no errors in XF86 logs. I've tried everything I can possibly think of.
Thanks for any help.