AX1000 high voltage?

[Blackcurrent]

I recently bought a new PSU, the AX 1000. Out of curiosity I ran some some tests off a molex with a Multimeter. When playing Doom Eternal the 12v rail goes up to 12.37v and stays there. When idling it's slightly lower. According to the ATX specification is is within the 5% tolerance. Is is exactly 3.1% above nominal, for such highly rated PSU this is not normal right?

[Alex Atkin UK]

14 minutes ago, Blackcurrent said:

I recently bought a new PSU, the AX 1000. Out of curiosity I ran some some tests off a molex with a Multimeter. When playing Doom Eternal the 12v rail goes up to 12.37v and stays there. When idling it's slightly lower. According to the ATX specification is is within the 5% tolerance. Is is exactly 3.1% above nominal, for such high rating PSU this is not normal right?

The rating has nothing to do with the voltage range, its about how efficiently it converts AC to DC.

In my experience a good PSU will prefer to stick to slightly above the nominal voltage rather than drift below it.  A good PSU should also have less droop and ripple under load, so again it shouldn't change too much.

If it were to drop from slightly above to slightly below, to me that would indicate a poor quality PSU.  The higher the wattage of the PSU, the less likely you should see it change as you'd only expect it to drift below nominal is when near maximum load.

[Blackcurrent]

What I meant was that this is a highly rated PSU, not its efficiency rating. The answer you gave me doesn't really say anything.  What is slightly above nominal voltage? 12.1-12.2? Is this voltage acceptable or not for long usage? Should I return it? 

 

I've been reading some reviews and the highest I've seen is 12.25v on load. Any experts here can share their opinion?

[Alex Atkin UK]

4 hours ago, Blackcurrent said:

What I meant was that this is a highly rated PSU, not its efficiency rating. The answer you gave me doesn't really say anything.  What is slightly above nominal voltage? 12.1-12.2? Is this voltage acceptable or not for long usage? Should I return it? 

 

I've been reading some reviews and the highest I've seen is 12.25v on load. Any experts here can share their opinion?

My point was that you answered your own question, its within the ATX specification therefore its fine.  The most important thing is its stable and as you'd need an oscilloscope to test the ripple, nobody can answer your question any more definitively than that.

[akio123008]

11 hours ago, Alex Atkin UK said:

In my experience a good PSU will prefer to stick to slightly above the nominal voltage rather than drift below it.  A good PSU should also have less droop and ripple under load, so again it shouldn't change too much.

In fact, preferably you'd have it at its maximum allowed value (12.6) to keep the load current as low as possible.

 

I'm not sure about the tolerance of the converters in PC parts, but I suspect some of them may tolerate up to 14V or so, which means in theory you could even mod a power supply to operate out-of-spec at say, 13-13.5V, which could come in handy if you're into extreme overclocking or something like that. 

[Guest]

12 hours ago, Blackcurrent said:

I recently bought a new PSU, the AX 1000. Out of curiosity I ran some some tests off a molex with a Multimeter. When playing Doom Eternal the 12v rail goes up to 12.37v and stays there. When idling it's slightly lower. According to the ATX specification is is within the 5% tolerance. Is is exactly 3.1% above nominal, for such highly rated PSU this is not normal right?

So, you have connectors with a load on them, and the PSU senses that loads and compensates any potential drop with an increase in voltage.  You, however, are testing an unloaded connector, which is going to have no resistance and therefore show maximum voltage.

 

If you were to put your multimeter's probe into the back of one of the PCIe connectors or put it on the EPS12V, you might find the voltage is much closer to +12V.

 

[Blackcurrent]

I tested with your method and now I'm reading a getting a 12.3v reading off PCIE that's attached to my GPU. Still pretty high. I also tested a RM850x and that one is reading 12.1-12.05 under load, much closer to nominal. Should I keep the RM850x and return AX1000?

[Guest]

3 minutes ago, Blackcurrent said:

I tested with your method and now I'm reading a getting a 12.3v reading off PCIE that's attached to my GPU. Still pretty high. I also tested a RM850x and that one is reading 12.1-12.05 under load, much closer to nominal. Should I keep the RM850x and return AX1000?

There is absolutely nothing wrong with 12.3V.  What you DON'T want to see is sudden spikes and drops.  That's the kind of thing that can damage parts down stream.   Not slightly high voltages that are still well within spec.