The best would be to run at 1:1 ratio with 175mhz FSB
dont run the mem over 400 it wont benefit your AXP a lot anyway. Synced ram/cpu is almost always better specially if you OC some...
Asus P4P800DX, P4C 2.6ghz@3.25ghz, 2X512 OCZ PC4000 3-3-3-8, Leadtek FX5900 w/ FX5950U bios@500/1000, 2X30gig Raid0