Undervolt Power Supply Fans

[2canSAM]

Hey guys I have a ThermalTake Purepower 480w that is serving me very well. My only complaint would be the noise. I was thinking of undervolting the 2 fans in the Power Supply to run a little slower but don't want to cause any issues with this supply. Would this be advisable?

 

[SerpentRoyal]

Probably not a good idea. Antec use this strategy with the SP line. Bad choice. PSU and caps overheated...RMA time.

 

[JEDIYoda]

Not a good idea at all!!

 

[2canSAM]

OK guess it's time to look for fans that are a little less quiet or a new PS.

 

[mpilchfamily]

Yeah fan replacment would be the better option.

 

[thecoolnessrune]

You should just replace the PSU with something quiet such as the Enhance 5150GH 500W, Corsair HX520 520W, or Seasonic M12 500 500W.

 

[RallyMaster]

Corsair HX520 and Enhance ENP5150GH are definitely recommended.

 

[mindless1]

Some of thermaltake's fans are junk that wear out quick. If that's the problem, you might try lubing them and/or replacing them. If it is only a matter of wanting lower RPM because that's quieter, replacing the fans won't gain you anything as you have essentially same situation with newer fans of lower RPM as you have with the original fans at lower RPM, presuming you are targeting the same RPM.

Reducing fan RPM too much can definitely lead to a hot running PSU which is not good over the longer term, but you may be able to safely reduce the fan speed some rather than a lot. The easiest way to do so would be to put a series resistor on the fans positive lead, something like a 2W 47 to 68Ohm per each fan.

If this PSU has a thermal fan control circuit in it, and you can tell it does respond well to changes in temp instead of being pretty dumb (miscalibrated) such that it doesn't change speed much within your regular usage (temp zone) even with the side panel off the case, then you might consider first improving the case ventilation (larger passive intake area or intake fan addition(s)) as that will not only help reduce fan speed (if it's not dumb as mentioned above) but will allow moving more air per any given PSU fan RPM.

Whether your caps would end up popping from a lower speed we can't predict any particular timeframe, nor could we predict if they'd pop anyway even if no change is made (pretty common for some mid-lower end PSU to pop caps even if left in stock configuration, BUT we dont' know how hard you are pushing this PSU, if not very heavily loaded it may do fine).

 

[Red Squirrel]

I often end up replacing PSU fans. You could undervolt them, but be extra sure you have plenty of positive air pressure in your case, so it will force air through the psu either way and the fans spinning will help too. I've done that a lot and never had issues. Just monitor it for a while to ensure it does not get too hot to the touch. (do not test this by touching the top of the capacitors. )

But sometimes a simple fan replacement will fix it by not touching the voltage. I would almost be willing to say you don't even need 2 fans in a PSU. Fans in series don't really add extra air flow. But it does help direct the internal air flow so it does help a bit I suppose. some PSUs do get pretty hot, but some don't get as hot. Really depends.