Overclocking help with Bios settings check.

My first post so Hi to All & Thanks for any help offered.

I put this system together from 2nd hand parts last week & need some experienced eyes to look over my settings as although the system runs 3D 06 perfectly it locks up whenever I run memtest. With the settings below the system runs memtest Perfectly using some Corsair that I have but no matter what I try I cannot get it to complete memtest using my Crucial. The Crucial is RMA got back Saturday after the last set failed memtest, Is it me or the ram ?
I have upped the Volts by 0.40 with the Crucial taking it to 2.21v to try to help but still it locks up within 5 seconds of starting memtest.
Being honest building this system has pushed me but I have had my head stuck in & out of the Bios so much recently that I think I am missing something obvious.
Any help/advice would be Greatly appreciated, thanks for reading.
JSB.

Xeon 3210 2.13GHz with AC Freezer 64 running @ 2.66GHz @ Below 60c under load
Gigabyte-P35-DQ6 Mobo. F7 Bios.
2 Gig of Crucial Ballistix DDR2 PC2-8500 CL5 EPP.
2 x X1950 Pro's in Crossfire. 8.6 Cats & CCC.
Antec Trublue 480w PSU.



RGB - Auto.
CPU Clock ratio - x8.
CPU Frequency - 2.66GHz (333x8).
CPU Host clock control - Enabled.
CPU host Frequency - 333.
PCI Frequency - 100.
CIA2 - Disabled.
Performance enhanced - Standard.
System Memory Multiplier(SPD) - 2.00.
Memory Frequency MHz 800 - 667.
DRam selectable Timing - Auto.



System Voltage Control - Manual.
DDR2 overvoltage - +0.40 bringing it to 2.21v.
PCI-E - normal.
FSB - Normal.
(G)mch - Normal.
Loadline Calibration - Auto
CPU Voltage control - 1.32500v


P.s.
Please feel free to ask any questions you feel relevent to help me out.