PSU voltage levels

[TrojanSquirrel]

Can anyone tell me what sort of voltage levels I should be getting. I have a PSU that is almost bang on on all the readings except for the +12v rail.

This is only kicking out 10.8v-11.4v when system idle.

I have tried putting the graphics card on it's own rail (no change) and disconnecting the optical drive (got an extra 0.5v).

Is this normal?

 

[Frank4d]

The ATX MOBO specification >>

http://www.formfactors.org/developer/specs/atx2_2.pdf

and ATX PSU Design Guide >>

http://www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2.pdf

both say the 12V rail should be within +/- 5%, or 11.40 to 12.60 volts.

Software based utilities like Speedfan and the BIOS are notoriously inaccurate though. Before running out to buy a new PSU you should check the voltage with a digital multimeter. If you don't have one you can get a fairly decent one for $20 and up >>

http://www.radioshack.com/product/i...&cp=2032058.2032235.2032305&parentPage=family

 

[johnbullas]

What wattage PSU running what equipment? (processor spec / motherboard etc etc) a low wattage PSU will struggle powering a PC designed for intermediate range weather forecasting

 

[TrojanSquirrel]

Thanks, just dumped in a Q-Tec 500w psu and all is well with the world. The 400w that was in before clearly was struggling. Now the 12v rail sits at 11.8ish.

The cpu is a 3400+ amd64, and the graphics are a ati x800pro.....

My first suspect was the psu, and it turned out to be so.

I have another machine that has the 5v rail down around the 3.5v mark (on a 400w psu with a 3400+ amd64 plus a ati 9800xt) and its running sweet. Is that normal?