PSU voltage rails a bit low?

Axegrinder · 06-03-2009, 12:32

Hi all, was just monitoring system temps and voltage levels, and noticed the 3.3v, 5v and 12v rails are abit on the low side.

Speedfan reports the voltages as:

3.3v is around 3.17-3.23
5v is around 4.41 to 4.65
12v is around 11.49

Are the within acceptable limits? The psu is a Sumvision 400w.

Cheers Axe

damien c · 06-03-2009, 12:44

try using everest to monitor the voltages if that is available on the free version, or you could always have a look in the bios see what they show when you first turn on your pc.

Axegrinder · 06-03-2009, 13:02

Looked in the bios and they are exactly the same as what speedfan reported.

Druchii · 06-03-2009, 13:04

I would replace it, Sumvision are total pants PSU wise.
I had two go BANG within a week.

As for them being under-rated, this is probably because of the load on them, or, the PSU is just craply built.

Axegrinder · 06-03-2009, 13:53

Forgot to mention it isnt my PC is the family desktop downstairs, I will replace it but im pretty skint at the mo

PSU has lasted 4 years though lol.

06-03-2009, 13:57

it depends what your running in it if its stable then I do not see much of a problem

Kymmy · 06-03-2009, 15:22

Remember that reported voltages on a motherboard are only relevant to however the reference voltage is produced..as it's strange for all the voltages to be low at the same time on seperate rails (unless your mains voltage is low?????)

In plain english that means that the method used to read the voltages might be the error and not the voltages itself...

Do you have a digital multimeter? If so that's the best way to confirm if there's a problem or not

Axegrinder · 06-03-2009, 15:30

I dont have a multimeter i'm afraid. The PC is stable though. I just wanted an opinion on the rail voltages to be on the safe side.

Matth · 06-03-2009, 21:30

That 5V rail looks like possible system crash level.

One thing to check, feel the PSU outflow, if the fan is failing, you will feel heat but no flow, I've seen PSUs throw irregular voltages when cooking due to a stalled fan, and they sometimes survive for a while if the demand does not cause an immediate burnout.

Axegrinder · 08-03-2009, 09:30

Update:

I have just installed a graphics card in the PC, but when i run a 3D appplication, the monitor goes blank after a min or so. Do you think the low voltages would cause this?

Druchii · 08-03-2009, 09:40

Yes.

Axegrinder · 08-03-2009, 10:20

Ok thanks, I will replace the PSU tommorow.