Quoted from Overclock.net:

Please read this if your overclocking is not stable and you require extremely high voltage.About a year ago i bought a new psu (ultrax3 1000W) and bought a 2600k. The reason i bought a 1000k psu was to run my SLI gtx 580, watercooling rig, plus 2600k overclock and have headroom for future upgrade. My 2600k overclock required 1.48v to reach 5ghz so i was happy with it.Now here is what i foundNow almost a year later my rig was not stable and i was force to run it @ 4.6ghz @ 1.440v because in order to reach 4.8ghz i needed 1.52v to get it stable. I thought that my cpu has been degrading over the year because of the high voltage i have been using. I never figure it was another problem. My rig would work beautifully only that my cpu required such a higher voltage now that i was thinking of replacing my cpu. I started noticing (with software) that my 12V PSU line dropped badly (around 11.66V) when under load while at idle was stable at 12v. I figure to get my multimeter and see how low my 12v rail really is, i also notice my 5v and 3v dropping. I was only concern of the 12v cause i run my videocards and almost everything with that line so i only check that one. With my multimeter my 12v rail dropped to 11.51v while load. I order a new ENERMAX MAXREVO 1350W (i know... overkill) but you cannot blame me cause it was only $209. After installing it i went to my overclocking and see if my psu was causing overclocking instability. Now i find out that i only need 1.424v to get 4.8ghz while with previous PSU needed 1.52v to get it stable (no settings were changed in bios other than the cpu voltage) That a HUGE different in voltage. i ran prime 12 hours rock solid stable while before prime would freeze withing a second at that voltage at the same or even higher voltages.I believe the voltage drop was causing very bad stability in my rig. My psu had enough power to run almost anything but it wasn't about power, it could not maintain a steady voltage.So please get a multimeter and check your line just for a peace of mine. You might not be stable because of your PSU.Do not blame ULTRA PSU cause this could happen with ANY PSU. over time the PSUs start loosing their power and degrade.Hope this help and sorry for my bad writing skills, english is not my native language.

After running flawlessly for months with 4.8GHz @ 1.40v, I got a BSOD a couple weeks ago. I dropped my OC down to 4.5GHz and bumped up the offset voltage a tad. Between downloading scenery 24/7 and finishing up my thesis, I couldn't afford to have my PC blue screening on me. I know it was said in the beginning that power delivery would be very important with Sandy Bridge, but we all assumed that would be in the form of the motherboard. Anyway, maybe somebody else having similar issues can look into this. I would like a new PSU, but I can't do it right now, nor am I concerned enough about it.Anyway, the whole issue reinforces why it's so important to get a good PSU.

Quoted from Overclock.net:After running flawlessly for months with 4.8GHz @ 1.40v, I got a BSOD a couple weeks ago. I dropped my OC down to 4.5GHz and bumped up the offset voltage a tad. Between downloading scenery 24/7 and finishing up my thesis, I couldn't afford to have my PC blue screening on me. I know it was said in the beginning that power delivery would be very important with Sandy Bridge, but we all assumed that would be in the form of the motherboard. Anyway, maybe somebody else having similar issues can look into this. I would like a new PSU, but I can't do it right now, nor am I concerned enough about it.Anyway, the whole issue reinforces why it's so important to get a good PSU.

I am purchasing the Corsair AX850 watt. Do you think it will be adequate?? (SPECS IN SIG)

The Corsair AX series and Seasonic X series are supposed to be about the best you can buy

I hope my HX can last a while. This has taught me a fair bit about PSU's, never thought much of them other than their efficiency and wattage.