I think that something is wrong with your machine...
My spec´s
AMD Sempron 2600+ 1.6GHZ L2 128kb Socket 754 Revision E6
DDR 256 PC3200 Kingston CL=3
Hard Drives IDE UDMA 5 Western Digital 40GB and Samsung 80 both´s 7200rpm.
Motherboard Asus K8V-VM Ultra Chipset Via K8M890CE
Audio Realtek chipset ALCxxx
Power Supply Logysis 480watts (total power 330watts)
Drives Optical= LG GSA-4163B Firmware A106 and LG GDR-8162B yeah i cant copy games for Gamecube....
Video card (it will update for one PCIexpress) PNY Verto Geforce FX5500 128DDR --- Clocks= 270mhz core, Memory 64bits 400mhz, Bus PCI card.
Drivers Omega 66.93
Default benchmark:
3DMARK 2001 SE
Score in 1024x768 32bit´s = 5435 3Dmarks (single buffer, all in stock, default in 3dmark)
Score in 640x480 32bit´s = 7635 3Dmark´s
Not is possible your score, maybe is bad config....
It will update soon with the image that verifies the score and spec´s.
Bye!!