E6320@2.5 Vista/XP Unstable?

[vir7uous]

CPU: C2D E6320
MoBo: 965P-DS3
RAM: G.skill DDR2 800 5-5-5-15

I've had this rig built for a week, been overclocked and stable @ 2.5Ghz (7x350) for the week, so today I decided to dual boot Vista/XP. (Im using the 'Dell OEM' Vista) and ever since i cannot restart Windows (Vista or XP) without my PC hanging at POST and resting my CMOS back to stock. The other things that change back are my PCI Freq (from 100 to auto) and my FSB (from 350 to auto) everything else stays the same. I'm able to boot once; either to Vista or XP overclocked, but i have to reset everything during restart.

1) Is this just instability? should i try a lower FSB?
2) or Is this a problem with Vista or Dual booting?
3) Anyone else had any similar problems?

 

[jay2tall]

Have you increased your vCore to obtain that frequency or is it stock? if it's stock try increasing your Vcore to 1.35 and go from their. Are you stock cooling this?

 

[vir7uous]

cooling is ACF7 (forgot to mention that) but yeah, it's cold, 28c idle, 55c max TAT. I guess ill give the boost my vCORE a notch.

is there a reason why id be 100% stable on XP but when i partition/dual boot xp and vista it would make it unstable?