A suggestion, have you tried switching memory around?
I was once working on a client's computer which was horribly horribly slow. Replacing the memory somehow fixed it, probably the stick was bad

And one final hint, you can set the cas latency in the BIOS from 3 to 2, if you haven't already. Unless you're running EDO or PC-66 memory in there it shouldn't cause any problems. Free speed 😉

Simon wrote:

edit: its only an 8mb voodoo 2 not a 12mb but id still expect better performance on quake 2. like 40 or 50fps i would have thought

Any luck yet? You might wanna have a look at this for some ref on V2 8mb vs 12mb performance and settings.
http://www.fortunecity.com/millennium/celeste … 07/timedemo.htm

Also, as Tetrium pointed out check the ram. Might wanna check the hard disk also while you're pulling things out. I had a bad h/d the other day in my P233MMX- eveything went shitty while I was figuring out what the problem was.