Changed my PSU but the 12v rail is still too high

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xispes

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Jul 24, 2015
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Hey everyone, I'm making this thread in hope of getting some feedback on what's wrong with my 'almost-3-year-old' build. Last week, my pc started shutting down every 15-20 minutes, so I went to check the BIOS if anything was wrong and I saw that the 12V rail is reading values upwards to 13.920V and 14.358V, sometimes even 15v before it shuts down (anti-surge protection).

"This isn't normal" I thought, maybe my PSU was going bad. I didn't have a multimeter with me at the time but after checking with other software I had the same readings, so I bought a new PSU, but the 12V rail is still too high. Just idling in BIOS, current values are at 13.632 and increasing every 10 minutes.

Now I'm thinking that I'll either have to buy another motherboard or a cpu, maybe both. I've check all connections, updated cpu drivers, removed CMOS and plugged it back again, switched ram stick and ran tests on it and checked dozens of other threads with similar problems. 5V and 3V values are normal and within the +10% margin, just the 12V that's giving trouble.

I would be grateful If someone could help me nail down this problem. Here are my specs:

CPU: Intel i3-2130 @ 3.4 Ghz
GPU: XFX HD Radeon 7770 1GB
MOBO: Asus P8H61-M LX rev.2.0 (microATX)
RAM: 2x4GB DDR3
PSU: [NEW] Mars Gaming 600W (MP600) [OLD] Nox NX 620W
OS: Windows 7 Ultimate Edition x64
 

xispes

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Jul 24, 2015
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So both of them are bad? I've had the old one for almost 3 years, running without problems and only now I'm having this issue.
 

PC T

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Jul 17, 2015
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Power supplies are a sensitive issue, look at how many amps the power supply can provide on the 12V rail before purchase.
And after a couple of years low quality power supplies tend to lose a lot more of their power than high quality ones. Looking at the length of the warranty gives a good idea of the quality of the build.
Corsair for example gives a 5 year warranty.

I also looked into the specs some more, your new PSU is called 600W, but delivers 420W on the 12V rail.
Compared to my 6 year old Corsair TX650, which delivered 648W on the 12V rail, when new.
Just looking at total wattage of a PSU is sometimes not enough, I don`t know the further specs of your pc, but you might be overloading the 12V-rail maximum power output
 

utgotye

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Don't touch Corsair PSUs unless you are spending a lot (RMi, HX, AX...etc). Quality units can be had from Antec, EVGA, Seasonic and XFX that don't break the bank. EVGA and XFX units have been on sale with/without rebate on a fairly regular basis over the last couple months.
 

xispes

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Jul 24, 2015
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Updating this thread as I've already solved this problem. Turns out that the problem wasn't PSU related. One of the RAM sockets in the motherboard was drawing too much power, and caused a huge spike in the 12V rail. There was no possible repair so I just replaced it with another and now everything's fine.
 
May 29, 2020
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Updating this thread as I've already solved this problem. Turns out that the problem wasn't PSU related. One of the RAM sockets in the motherboard was drawing too much power, and caused a huge spike in the 12V rail. There was no possible repair so I just replaced it with another and now everything's fine.
so you just replaced a ram stick and it fixed? I have the exact same problem
 
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