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UEFI bios shows overvoltage on 12V rail

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Sep 8, 2002
Dublin, lreland
The system shutting down now fairly frequently, and had to reset CMOS. Eventually got it to boot into bios.
V12 rails shows up to 18V, then comes down gradually, and after about a min it drops to 12.7V. I can boot into windows then, but it does not last long before shutting down.

Is it likely to be the PSU or the MP (both i think are showing their age).

Just checked a couple of molex's with a VM and voltage is 12.13 consistent, but on bios fluctuating at over 15v. I'm starting to think its the MB.

Any comments welcome.

MB is ASUS P8Z68-V LX, and psu is antec truepower 650w.
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Thanks for the link. Actaully pretty ofay with the MM, and have now checked the PSU 12v rail off the MB, and all outputs are solid 12.12V-12.13V with no load. With me little understanding of voltages, while you can get voltage drop from the PSU for many reasons particularly under load, likelihood of having an 18v output from a 12 volt rail is pretty unlikely, without actually smoking something....

So I took a gamble and switched off overvoltage, and now back into windows to do some testing. I've checked the molex with full load, and running prime95 and its solid at 12.11v (0.02drop with load!). Though i have yet to get back to me overclock!. Will try stock first.

Alternative was to ditch the motherboard, and rebuild, since the 1155 boards of any decent quality are hard to come by or way overpriced. So nothing to loose. ...............

Running stable for a couple of days now @ 4.0ghz. So issue is with bios reporting of 12v rail.
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