What exactly is a 'quiet' PSU?

By Snowy Commando · 14 replies
Sep 28, 2002
  1. It may seem like a question with an obvious answer but I just wondered...... :rolleyes:

    My current Aopen 300W PSU is fine apart from the medium-pitch electrical whining noise that the PSU makes like i've heard before with all other PSU's that come supplied with a case. Out of all other components the PSU is one of the only things I've never replaced with a branded one like Enermax for example.

    I can tell theres a definite difference between fan noise and electrical noise. Fan noise is avoidable with fan control but electrical is dependant on the actual device making it which is only the PSU.

    Does a "quiet" PSU mean it has far less fan noise and/or electrical noise?
  2. Vehementi

    Vehementi TechSpot Paladin Posts: 2,704

    My PSU is supposed to be silent (Enermax Whisper), and I don't hear it above my 5 case fans and the 60mm fan I have spinning at 5k RPM on my GFX card.

    I think it depends on the brand. Good, quality brands like Enermax, Antec, etc. silence their PSU's as much as they can. But other, cheaper brands just put lower-RPM fans on to denote "silent".
  3. Mictlantecuhtli

    Mictlantecuhtli TS Evangelist Posts: 4,345   +11

  4. Snowy Commando

    Snowy Commando TS Rookie Topic Starter Posts: 148

    I found my AOpen case to be a good all rounder with plenty of room for expansion and I assumed that because the PSU was also the AOpen brand it would make some difference to noise.

    Its no quieter than my previous case. I may consider a new PSU eventually as if they run at 25-30dB as advertised, they will be very quiet indeed.

    PS. for the record, the electrical noise I speak of from a PSU can be more commonly known as the "audible coil buzzing" component inside of it.
  5. Per Hansson

    Per Hansson TS Server Guru Posts: 1,959   +218

    I assume the noise you refer to is the same a TV or computer monitor also can emit, it's extremley high pitched, for example my father can't even hear it but it drives me crazy...

    My new TV has that problem when it starts but after just a few seconds it disappears, I guess it changes some frequency to get rid of the noise somehow...

    A friend to me however has an older TV and that one starts to emit the noise after a while, presumable when it has gotten warm, and it doesn't stop if you don't turn of the monitor and let it cool of...

    I have just the exact same problem with an old 14" computer monitor, but I found out that if I change the frequency with powerstrip down or up a few hertz the noise stops...


    But back to your Q, what the PSU manufacturers refer to is that the fan is thermalcontrolled, i.e. if the PSU is cool the FAN will slow down and counterwise when it gets hot...

    I have a 431w Enermax PSU myself and it's one extremley quiet PSU I must say, highly recommended!

    On a side note I've never heard a PSU emit this "electrical noise" (which I also explained above...)
  6. Snowy Commando

    Snowy Commando TS Rookie Topic Starter Posts: 148

    PSU "electrical noise" = the high pitch whine emitting from it as well as the PSU's own fan noise.
  7. Vehementi

    Vehementi TechSpot Paladin Posts: 2,704

    Your PSU emits a high-pitced whine? :confused: I haven't heard any from my 400w.
  8. Snowy Commando

    Snowy Commando TS Rookie Topic Starter Posts: 148

    Thats because u have an Enermax Whisper. :p

    Apparently, Scan have very cheap own-brand PSUs which all claim to use "Active PFC", "Dual Fans" and "Super low noise" from £30 upwards. I'll have to find out more about these. :cool:
  9. Mictlantecuhtli

    Mictlantecuhtli TS Evangelist Posts: 4,345   +11

    My theory is that you only hear this coil sound from (low-quality) PSUs when they're under heavy load. I have two PSUs in my computer right now and the other, older one, makes some noises every now and then. Not loud but it's audible because the system itself is quiet.
  10. Snowy Commando

    Snowy Commando TS Rookie Topic Starter Posts: 148

    Another interesting thing are these New PSUs from Hiper PC Ltd.

    The only review here claims they are "Enermax beaters" and i have seen them @ eBuyer for "at least 25% cheaper than Enermax".
  11. Elcarion

    Elcarion TechSpot Paladin Posts: 169

    I suggest replacing the fan in the PSU with an 80mm from Panaflo or Papst; this is the cheapest, most effective way to quiet the PSU fan noise. I did this on my Antec PSU with Thermally Controlled fan, it's now whisper quiet. The Papst is worth the slightly higher expense than the Panaflo, IMO. In addition, a wire fan grill will be quieter than a grill made of flat, pressed metal. Most cheap PSUs have a grill pressed out of the PSU casing...cut it out and replace it with a wire grill when you replace the fan.

    The loudest thing in my system now is the HD! I reduced the sound of the HD around 50% by relocating it but it's still a bit loud. Good Luck!
  12. Vehementi

    Vehementi TechSpot Paladin Posts: 2,704

    IMO as well. Papst fans are excellent because they balance them perfectly, eliminating any vibration at all.

  13. young&wild

    young&wild TechSpot Chancellor Posts: 993

    Hey, Snowy

    I think i got the same prob with ya, got this cheap 300w PSU last Christmas...It's a bit noisy with some screeching noises from the fan during booting.
  14. Elcarion

    Elcarion TechSpot Paladin Posts: 169

  15. Th3M1ghtyD8

    Th3M1ghtyD8 TechSpot Paladin Posts: 664

    Electrical whining noise is caused by cheap components, I know from experience of buying cheap cases with cheap PSUs. Does yours whine even when the Power Switch is turned off (i.e. still plugged in to socket, turned on, but ATX switch not pressed), drove one of my customers mental :D till I bought him a more expensive PSU.
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