First try turning down the video settings for quake 3. Also use the wickedgl driver for the Voodoo 3. How much ram do you have? You should have 128 megs to stop hard drive thrashing.
http://www.game-files.com/details.asp?Name=471 latest wickedgl driver.
[Edited by sbp on 09-29-2000 at 12:32 PM]