Why??

I have a Geforce 3 and a very good system (See my signature for config). Why would my 3dMark 2001 score go down from 6900 to 6645 when all I did was install a better hard drive?
I switched from a Western Digital 5400rpm to a IBM Deskstar 7200rpm ATA100. I am running Win ME as my OS.

Got your 4in1 drivers installed?

Check your control panel for anything fishy.