Take that thing with a grain of salt... I just tried it, and ranked my system VERY low.
Processor AMD Athlon(tm) 64 X2 2210MHz
Display Card Generic VGA
Operating System Microsoft Windows Server 2003
Free Disk Space 140.62GB
Display Card Memory 256MB
Display Driver Version 188.8.131.52
DirectX Version 9.0c
Optical Drive CD/DVD
Sound Card NVIDIA(R) nForce(TM) Audio
Display is actually a brand new Nvidia 7600GT (more precisely, the XFX 7600 GT XXX). It's an awesome machine, possibly the tool has issues with the just released line of Geforce cards, or with 64bit versions of Windows XP.