Get Coolbits and let it auto-detect the best OC for you. I've noticed that I sometimes get WORSE performance with higher core/memory speeds, even when the settings pass Coolbits' testing.
That's about right, I get the following with a PIV 2.4B, 1 gig DDR333, Forceware 53.03, all stock speeds...
3D Mark 2001SE 12,994
3D Mark 2003 5604
But I don't care too much for synthetic bench scores, all I know is I can now turn on every detail in NFSU and get a very smooth framerate with no hiccups or pauses, I can play Splinter Cell with every detail maxed out and it's very smooth and even in the heaviest fire fights in a small, crowded hall way with everyone letting off rockets in UT2K3 I don't stall out like I used to (with everything on highest settings). Don't worry about the pissing contest, worry about gameplay.
You may be held back a bit by your processor...the 2000 is getting a little long in the tooth these days. Otherwise those scores aren't too bad for your config.