PSU 12V rail spiked to 20V

[grammitt]

I have a Corsair HX750 that I've been using without problems for almost two years now. Today the 12V rail on my power supply just randomly spiked to 20V, returned to normal, dropped to 0V, returned to normal, and has stayed at normal for a while now. (http://imgur.com/OveiLom) This morning I used the Asus overclock utility to oc my cpu from 3.4GHz @ 0.9V to 4.2GHz @ 1.15V. I did the same overclock the same way before almost two years ago when I built my computer and had it at that speed up until last month when I updated the BIOS, which resets the overclock parameters. I can't find any information about this anywhere else and this is making me very nervous.

Specs
CPU: Intel i5 3570k @ 4.2GHz @ 1.15V
CPU cooler: CM Hyper 212 EVO
Mobo: Asus P8Z77-V PRO
RAM: Corsair Vengance 8Gb 1600MHz
GPU: 2 Sapphire 7950s in crossfire
SSD: Samsung 830 EVO 128GB, Samsung 840 EVO 250GB
HDD: WD Caviar Black 2TB, WD Caviar Blue 1TB
PSU: Corsair HX750 750W

 

[Dark Lord of Tech]

Overclock from the BIOS , software overclocking is not a great idea.

 

[grammitt]

Ok but I had that overclock stable for almost two years. Why all of a sudden would the 12V rail spike so high? I've also read that the software monitoring programs can sometimes misrepresent the actual values. Could this be a possibility? I want to be sure whether this is an actual serious problem or just the software being dumb.

 

[Dark Lord of Tech]

I think it was a glitched\bad reading your power supply is a great one.

 

[hunter315]

You couldn't get a reading of 0V on your 12V rail, your system would have turned off, you also couldn't get a reading of 20V on your 12V rail, your system would have burned out. Software voltage readings are not accurate.

 

[grammitt]

Yea I kinda figured that those voltages couldn't be possible, seems that all evidence points to inaccurate software readings.