memtest results - pls help

i'm trying to figure out if my memory or my cpu is my current bottleneck.

my system is perfectly stable up to 255 fsb. When i go to 257fsb, it becomes highly unstable, and memtest86 gives me thousands upon thousands of errors. I get the same amount of errors at 257fsb using either my corsair pc4000 or mushkin pc3500 (bh5). Doesn't matter if i drop the divider or stay 1:1.

If it's my memory holding me back, should i try to relax the timings? If it's my cpu, should i up the vcore?

System:
P4 3.2C @4.1GHz (255fsb). p4c800e (droop mod + vdimm mod), 2x512MB Corsair XMS extreme 1:1, 3:4:4:8, 2x160 sata raid0, ati 9800 pro (vdimm mod, vcore mod, mcw-50t tec), water cooled nb, antec 550w true control ps.

It may be your chip maxing out. Try increasing the vcore but don't go crazy with it unless you've got excellent cooling. I know most BH5 chips can do speeds in excess of 250MHz with tight timings so long as they've got plenty of vdimm (they love voltage). But, to eliminate the memory as a problem try doing one of two things: 1) loosen the timings or 2) raise the vdimm.

~THT

which bios version your running ?

i'm running the 1015 bios. i have a prommy mach1 so cooling isn't really an issue, my temps are around -22C. i've upped the vdimm to 2.95V and vcore to 1.65 and get the same result. i'll loosen the timings, and if that doesn't work, i guess i'm at my max with the cpu.

yeh, I'm guessing you're at your max