low voltage on 12V rail of psu.

[Dadrian Daedalus]

I recently bought a CX 450 psu for my computer.After installing it i checked the voltage readings of the psu in windows using hwinfo64-the voltages in all rails appeared stable,apart from the one on the 12v rail,which measured around 11.88v on idle and 11.59-11.66v upon load.So this caused me some concern as the voltage appeared to be somewhat on the lower side.

I was told to check the readings using a multimeter,so i tested the 12v output of a spare molex connector using a generic dt830 multimeter that i had at my disposal.It would have been ideal if i had measured the voltage from the 24pin atx connector but as it was already plugged in to the mobo and removing it would have been pretty cumbersome,i decided to test the molex connector instead.

After testing the molex connector i discovered that the output of the 12v rail was around 12.27v upon idle and 12.29-12.3 volt under load(as opposed to 11.88v and 11.66v for idle and load respectively as was being reported by hwinfo64).

So i wonder which reading is more accurate?Are readings taken using software like hwinfo reliable at all?If i go by the measurements that i took using the multimeter,would it be safe to assume that the psu is operating normally and is not defective?

Also is the 12v output of a psu fairly consistent across all of its connectors or is it likely to vary between them by a significant margin?What i am trying to say is,could it be that,even though the molex connector is receiving 12.3v during load,the 12v output of the atx 24pin connector is actually much lower and is around 11.66v(like hwinfo is reporting)?

My pc config is:i5 cpu,gigabyte b75m d3h motherboard,8gb ram,650ti gpu.

 

[JalYt_Justin]

Software measurements can be misleading and some of them don't even really work at all. The one that was measured with the actual multimeter is likely significantly more accurate.

At any rate, it's usually 12V +- 5%. So you're still at a very fine spot as far as voltage goes, considering the "safe" maximum is 12.6 and the "safe" minimum is 11.4V.

No worries.

 

[Dadrian Daedalus]

Ok,since the output from the molex connector hovered around 12.27v-12.30v (which was significantly higher than the readings displayed by hwinfo under idle and load conditions),can it be assumed that this is the actual voltage that the motherboard is receiving from the psu's 12v rail?

What causes such a tremendous disparity between software and dmm readings?

And what symptoms can i expect to observe if the voltage on the 12v rail of my psu goes above or below the safe thresholds?could it result in system instability?

 

[JalYt_Justin]

Ok,since the output from the molex connector hovered around 12.27v-12.30v (which was significantly higher than the readings displayed by hwinfo under idle and load conditions),can it be assumed that this is the actual voltage that the motherboard is receiving from the psu's 12v rail?

What causes such a tremendous disparity between software and dmm readings?

And what symptoms can i expect to observe if the voltage on the 12v rail of my psu goes above or below the safe thresholds?could it result in system instability?

It'd be better to check PCI-E connectors or the 24-pin connector from your PSU.

The disparity is the fact that software cannot be fully accurate. It goes through the motherboard and many layers of hardware and software before it reaches your eyes. There could be any number of issues present with that. This is why we say to use a multimeter.

System instability is the most common with either lack of voltage or too much voltage. With high enough instability, especially on the high end, it could damage parts.

You're not at that point, so you're fine.

 

[Dadrian Daedalus]

Ok,since the output from the molex connector hovered around 12.27v-12.30v (which was significantly higher than the readings displayed by hwinfo under idle and load conditions),can it be assumed that this is the actual voltage that the motherboard is receiving from the psu's 12v rail?

What causes such a tremendous disparity between software and dmm readings?

And what symptoms can i expect to observe if the voltage on the 12v rail of my psu goes above or below the safe thresholds?could it result in system instability?

It'd be better to check PCI-E connectors or the 24-pin connector from your PSU.

The disparity is the fact that software cannot be fully accurate. It goes through the motherboard and many layers of hardware and software before it reaches your eyes. There could be any number of issues present with that. This is why we say to use a multimeter.

System instability is the most common with either lack of voltage or too much voltage. With high enough instability, especially on the high end, it could damage parts.

You're not at that point, so you're fine.

thanks for replying.So far i have not faced any signs of system instability and my pc appears to be working normally.

Why is it recommended to test the pcie or the 24pin atx connector?Is the 12v output from these connectors likely to be different from that of the molex connector?If yes,how much of a difference can we expect?

 

[JalYt_Justin]

Ok,since the output from the molex connector hovered around 12.27v-12.30v (which was significantly higher than the readings displayed by hwinfo under idle and load conditions),can it be assumed that this is the actual voltage that the motherboard is receiving from the psu's 12v rail?

What causes such a tremendous disparity between software and dmm readings?

And what symptoms can i expect to observe if the voltage on the 12v rail of my psu goes above or below the safe thresholds?could it result in system instability?

It'd be better to check PCI-E connectors or the 24-pin connector from your PSU.

The disparity is the fact that software cannot be fully accurate. It goes through the motherboard and many layers of hardware and software before it reaches your eyes. There could be any number of issues present with that. This is why we say to use a multimeter.

System instability is the most common with either lack of voltage or too much voltage. With high enough instability, especially on the high end, it could damage parts.

You're not at that point, so you're fine.

thanks for replying.So far i have not faced any signs of system instability and my pc appears to be working normally.

Why is it recommended to test the pcie or the 24pin atx connector?Is the 12v output from these connectors likely to be different from that of the molex connector?If yes,how much of a difference can we expect?

No, it shouldn't be any different from a molex connector but those are the two most direct sources of +12V power, which is easily the most important. Molex is fine though.

 

[Dadrian Daedalus]

ok,i will still test the pcie connector as soon as i get an opportunity,others have suggested me to check the 24pin atx connector but that entails disconnecting it from the motherboard which in itself is quite a cumbersome process to say the least.So i hope testing the pcie connector alone will give us a clearer picture of what the actual 12v output of the psu is.