White Screen Of Death??

[Danm54]

Ok, im currently overclocking my i5, been doing a little at a time and Prime Blend testing for a couple of hours at sort of .2ghz intervals from 3ghz up.

Now all is fine with a few tweaks untill i hit 3.9-4ghz, then about 10mins into the Blend test i get a white screen, loss of power to the mouse and keyboard and have to turn my PSU off to reboot the pc, power button does nothing.

This has happened twice so ive dropped back to 3.6ghz and im currently Blend testing now.

Any ideas?

System specs are

i5 CPU
ASRock P55 Pro mobo
4gb DDR3 @ 1068
GTX 260, not OC'd

Voltages

Vcore 1.4v in BIOS
QPI/VTT 1.21v
PCH 1.079v
CPU PLL 1.853


If my research is correct then PCH is the southbridge volts, so which one is my northbridge?

Thanks

 

[Akempster]

the northbridge voltage name will be found in the mobo manual

 

[Danm54]

Cant find it in the manual, ill have to dig out the support CD.

Its the white screen thats worrying me, im assuming its an overclocking issue not a graphics card issue.