psu problem????

snaggster · 28 Feb 2011 at 17:14

Hi folks. My overclock became unstable and i was getting stuttering in games. I reset cmos and tryed @ stock, the same thing was happening, and was also unstable in ibt.
I tryed playing a video file, that was also stuttering so i turned of hardware acceloration to rule out gpu. it was just as bad. After running memtest and other tests it came up clean.
After pulling my hair out, i had a look at hwmonitor in cpuz and it showed that my +12v rail was only 10.6v.... :eek:

.. I then got my trusty muilty meter out and that confirmed that it was ideed only 10.66v.
I just want to make sure that it will be my psu which is at fault? Before i go spending my pennies.
Just for referance my psu is a northq black magic 850w.

bremen1874 · 28 Feb 2011 at 17:33

The tolerance on +12V is 5% (I think) so anything under +11.4V is a potential problem.

snaggster · 28 Feb 2011 at 17:37

Just what i thought.... I cant belive it will even boot with only 10.6v.
Though timing was good for the antec deal...lol

Tealc · 28 Feb 2011 at 17:40

Anything less than the 5% deviation (11.4v-12.6v) allowed by the ATX standard is a cause for concern. If it's dropping to 10.6v then it's clearly not managing to provide good power and is suspect.

What about trying a different rail? Although from what I understand PSUs only produce one 12v rail but have it split virtually into rails by using current limiting devices.

Did you test and get the 10.6v while the PC was running? If you did then it might be worth testing the PSU when it's not plugged into anything.

snaggster · 28 Feb 2011 at 17:46

Did you test and get the 10.6v while the PC was running? If you did then it might be worth testing the PSU when it's not plugged into anything.[/QUOTE]

Yes i plugged in my multi meter before i booted. it stayed at 10.66v right though to start up, and @Idle. I then ran ibt and it droped to 10.6v under load. I also got very simular reading in both hwmonitor and the bios.

Tealc · 28 Feb 2011 at 18:36

Not quite what I meant though. Throughout that tets the PSU was loaded by your PC components.

What I had in mind was a test where you disconnect all PSU plugs, cross the green wire on the 24pin connector with a black, connect a fan and measure the voltage there.

It's probably not worth bothering with though as if it's being dragged down to 10.6v then it's clearly not a healthy PSU.

snaggster · 28 Feb 2011 at 20:41

Well after looking back though old emails it turns out that the psu is only 18 months old, so im going to RMA it. I have ordered the antec 750w that has just come on as a latest deal.