Grafics held/not held back by CPU power?

[QuietFlight]

I'm specifically talking about the fx5900 series cards.
I been lookin around and it doesn't look like there is much worth in upgrading my cpu power, well at least in respect to the 3dmark03 scores i see.

for example:
His RIG: P4(HT) @ 3250mhz @ 250fsb -And- 5900xt @ 500/780mhz
My RIG: P4(non HT) @ 2456mhz @ 153fbs -And- 5900xt @ 472/852mhz

His scores:-------------------------->My Scores:
overall: 6488 ----------------------------------->6240
cpu: 823 ------------------------------------->624

gt1: 211.2 fps------------------------------->182.5 fps
gt2: 46.1 fps--------------------------------->45.5 fps
gt3: 37.4 fps--------------------------------->36.1 fps
gt4: 38.3 fps--------------------------------->39.4 fps
Fill Rate(ST): 1474 MTexels/s---------------------->1704.5 fps
Fill Rate(MT): 3406.1 MTexels/s------------------->3379.9 fps

I may be being overly dependent on 3dmark results but AquaMark 3 Scores state parallel results.

Thier rig:
Athlon XP3200+ -and- FX5950 stock: GFX 5921/ CPU 9206

My rig:
P4 1.6A @ 2456mhz - and FX5900xt 472/852: GFX 5901/ CPU 7298


Is it worth upping my Proc to a 2.4C(OC'in it to 3.3ghz+ is a given)?
As far as these results are telling me the impact it has on Grafics perfomance is minute.