CPU: AMD XP 1800+ oc 2100 (211*10)
RAM: BH5 256Mb x2
Motherboard: Abit NF7 v2
VGA: ATI 9800 pro 256 Mb (R360) to 9800XT (412/730)

3Dmark 2001: 17800

I think the good solution is use K8 CPU which might get more than 20000 scores in 3Dmark2001.

So...R8500 is suitable in your current computer.