Amd Athlon 1.2 ghz system on K7T Turbo-R mobo, 256 megs PC150:
1) With a Visiontek GF2 GTS (Which is faster than your card) gets 3D Mark 2001SE score of 3400 or so
2) Same system with Visiontek GF3 Ti200 gets 3D Mark 2001SE score of about 6200
3) Your system with same processor, extra 256 megs of ram, and GF4 Ti4200 128 meg card would get an even higher score than that, probably some where around my score using an Athlon XP and DDR memory (just under 8000 3D Marks), or possibly higher!
Enjoy your new video card!