<< Make sure you don't have antialiasing turned on.
Try using the newest drivers from nvidia's website.
Try overclocking your video card a little bit using NVMax or Coolbits.
Increase your motherboards FSB (Front Side Bus) a bit.
Disable all programs running in the background, like anti-virus, instant messenger, etc, that you can. >>
All good suggestions. Let me add a few more:
Even though 3DMark says Anti-aliasing is turned off in the default test, if you have it on in video properties, it HURTS your score. So make sure it's "off."
In D3D properties, set the Mipmapping level to "Best Performance." This gains me 100+ points on my score.
Do NOT have 3DMark2001 skip the title screens between tests. Doing so costs me about 800 points. I know, you'd think it wouldn't have an effect, but it does.
DO look up on the net on how to do the "Coolbits" registry tweak. This allows you to use nVidias drivers to over clock your card, instead of a third party utility.
And everyone here is right. Your score is being held back by your lack of memory bandwidth. Using SDRAM with a P4 is like buying a race horse and cutting off it's legs at the knees. However, changing to RDRAM will more than likely require a new case, because you'll need a new motherboard and Sony uses proprietary parts.
If this is a new computer, don't bother. Enjoy it for now and worry about it when it starts lagging on games you want to play. There's no reason to throw this computer away.
BUT, if you're going to upgrade to RDRAM, I suggest building a new computer, and leaving the Sony alone, or parting it out to fill your new computer, i.e., use the video, sound card, drives, etc...