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12v showing on the 5v rail? PSU shot?

As the topic says, why would CPUID HW monitor be showing 12V on the 5v rail? Can I safely assume that the power supply is shot? What other components have been at risk from this voltage?

The computer in question is an old one from a friend. The video stopped working and a local shop told him that the motherboard (Intel DP55WB, lga1156, core i5) was shot. He bought a new computer and gave me the old one. I replaced the video card with an old one I had laying around and the computer booted right up. It ran just fine through several hours of Windows 7 installation and updating before I put the hardware monitor on it.

I intend to replace the psu anyway in order to upgrade the video card to something like an R7 265, but I'm just curious to know if something on the motherboard may have actually been damaged by that 12v on the 5v rail?
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  1. Just about anything electronic. The USB, hard drives, optical drives etc. Anything with an electronic chip.

    If it is really giving out 12V then it is seriously messed up. You could check with a multi-meter. The 20/24 pin has a few 5V as do the old molex connectors.
  2. I will do that, thanks. A lot of the stuff I've been reading say to never fully trust the voltages given by software monitoring, but that reading is waaaayyyy out. The good news is that absolutely everything else on the computer works fine. If I hadn't fired up the monitoring then I would never had known there was a problem.

    I might just leave it turned off until I line up a new psu. It's a 400w Allied brand that I have no interest in using anyway.
  3. Thats because HW Monitor is sorta just winging it with voltage readings these days, don't trust software voltage readings period. None of them are consistently reliable. Odds are it screwed up which rail goes where. Check in BIOS if you want real readings.

    Are you having an issue? If no, stop checking your voltage readings, they are just going to make you freak out about nothing.


    Things that would be dead if you had 12V on the 5V rail - SATA/PATA drives would have their micros cooked, PCI cards wouldn't work, any USB device you plugged in would be in trouble, and you would have blown a couple of the small micros on the main board.
  4. Best answer
    Nice. Thanks guys for the quick answers. I'll take a look at the bios and try to find my multimeter anyway, but it sure sounds like a goofy reading. Wish I could pick both of you as best answer!
  5. Hi, if you had 12VDC on the 5VDC rail, nothing will work on your motherboard.
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