Semi old system oc'ed

Specs:
P4c 2,8 Rev.D1 (250 x 14 3500MHz) 1,725V
Asus P4C800-e Dlx. AMI Bios v.1016.001
2x512MB OCZ 4000 EL Gold Rev.1 2,5-3-3-6 2,8V

Sapphire x850xt 590gpu/550mem
Latest Catalyst & chipset drivers. On-board sound.

WD 74GB Raptor c:\win f:\games
WD 120GB Caviar SE Sata d:\temp e:\progs
WD 120GB Caviar SE Pata x:\div

XP Pro Sp2 & updated n' tweaked with gameXP, regedit32
Watercooled with DD rbx, maze4, big radiator...

I get 13'500+ in 3dmark '03 and ca.5'800 in '05...
Seems a bit high...
A friend has same setup, but an slightly oc'ed FX55 and DFI nforce4 ultra
with 1,5-2-2-5 timings. I dont remember further specs like htt, V, etc...
and he gets 12'000 in '03... (pci express version of x850xt of course)

Whats the average performance with a similar system like mine?

Sin.
Thomas