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Thread: Is 3.4V output on 3.3V rail safe?

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    Default Is 3.4V output on 3.3V rail safe?

    I have a pc with the following config:

    core i5 3450,asus p8b75-v motherboard,12gb ddr3 ram,gtx 960,1+2tb hdds,seasonic s12ii 620w psu(the newer model).

    Earlier i had a power corsair vx 450 psu but i replaced it with the seasonic unit last year in january.

    Recently while monitoring the output voltages of the psu using aida64 ,i observed that while the readings for all other rails appeared to be normal,the reading for the 3.3v rail was a bit on the higher side-around 3.42v to be precise-it was fluctuating between 3.39 to 3.42 volts and sometimes(quite rarely though)increased to 3.45v for a few seconds.

    I'm aware that software readings aren't necessarily accurate,but if my psu is indeed generating 3.4v on the 3.3v rail then is it safe to continue using it any further?Will an output of 3.4v potentially damage any components of my pc?

    The psu was only purchased last year and has about 4 years warranty remaining-is there any cause for alarm due this issue and do i need to have the psu rma'd?My system is functioning normally though and i haven't noticed any stability problems or other issues with it whatsoever.

    Please advice what i should do-your inputs will be greatly appreciated.

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    Two things:

    If the voltage actually was 3.4V, you'd be fine. +/- is 5% (so upwards of 3.465V).

    Second: You can't use software to accurately measure a power supply's voltages unless the PSU has a means to deliver that information to the software (like a
    PSU with DSP).

    If you want to accurately measure your PSU's voltages, you should use a multi-meter.

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    Thanks so much for the prompt reply.

    Yeah,it hovered between 3.40-3.42v for the most part,but on a few occasions did rise to 3.45v for a couple of seconds.So will it be ok to continue using this psu in this situation?(assuming that the software readings are accurate)

    What problems am i likely to face if the voltage on the 3.3v rail goes out of spec?Will it cause any kind of system instability/crashes etc?Which component(s) of the pc will be directly affected as a result of this?

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    Quote Originally Posted by ssm002 View Post
    (assuming that the software readings are accurate)
    The software readings are not accurate.

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    In addition, software often reads voltages with a limited precision, like let's say 8mV or 10mV steps. It depends on the voltage reference used and the ADC in the super-io chip on mb.
    So for example, you could have 3.34v but software could say 3.4v, because anything between 3.32v and 3.4v would be rounded up.

    Use multimeter for accuracy.

    Anyway, these days very few things use 3.3v and they're not very sensitive to exact voltage.

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    ^Well in that case can i assume that the psu is ok as long as the output doesn't exceed 3.465 volts?

    I know that the measurements made using software are always likely to be error prone-its just that the voltages of all other rails appear well within spec,only the 3.3v rail's output seems marginally higher.

    According to a review of this psu i found elsewhere,during tests to gauge its performance in real-world scenarios,it idled at 3.44v,which increased to 3.45v under load conditions-could it possibly indicate that its like this by design and its 3.3v rail's output is slightly higher than what we are generally used to seeing in other psus?

    This is the review i was referring to(its in russian but was translated to english by google-i do hope its findings are accurate):

    https://translate.googleusercontent....8aTT7dGCBLn6zg

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    If you really want to know if your voltages are good, buy a multi-meter.

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