yea those sound a little low. i have the same card, abit siluro ti4400, and at 1.53 ghz i get 9033 3dmarks. i wouldn't think that 330 mhrz would make a difference of 2000 3dmarks...
you should try the latest leaked detonator drivers. last week they were 29.40 for XP and 29.41 for 98.