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I currently have a Corsair CX430 V2 PSU in my desktop:

However, it's extremely loud, especially when I do any resource intensive work (running a VirtualBox instance, playing a game, or just on a hot day). I want to replace it very badly, however don't want to just buy another PSU that's just as loud (or only slightly quieter). I'm also having some trouble because I'm an English speaker, and find lots of reviews on PSUs and suggestions online, but living in the Czech Republic, the PSUs available locally are rarely ever the same or find-able by similar model numbers.

So, I was looking for some general guidelines on selecting a PSU that will hopefully run quietly 90% of the time. I can understand if I'm really cranking it with a game that it may run louder some of the time, but it's extremely frustrating to have a loud PSU going even when I'm just doing normal work.

The main question I have, which I can't find much about on the net, is this:

  • If I only need about 400-430W of power output (AMD PhenomII, NVidea GTX460), does it help to buy a PSU that has a larger output capacity? ie. 550, 650, or even 750? The reasoning being that since it's built to handle larger power throughput, that during normal operation it's only going to be putting out ~400W of power and therefore it's fans will run slower and quieter. This could be completely faulty logic, but I can't find any info on this.

  • If that's not the case, then I'm assuming the opposite would be true? To get as close to what I need without going too much over?

I'm just looking for some general rules on how I can select a replacement PSU at a local computer store simply based on it's specs, and not on user reviews which may not match up directly to the selection I have available to me.

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Buy PSU on Ebay... –  Lazy Badger Nov 23 '11 at 14:53
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migrated from electronics.stackexchange.com Nov 23 '11 at 14:10

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2 Answers

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You're right with your reasoning in your 4th paragraph - a high capacity PSU under low load will not need to cool itself anywhere near as much as a lower capacity drive running (struggling!) at high load :)

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Thanks! I will look for a higher capacity PSU, 120mm fan, and one that says its "low noise" and hope that normal load will keep it quiet. :) –  Nick Jennings Nov 23 '11 at 17:50
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Running a PSU at about halfish load allows for better efficiency as well. Since I would guess you need about ~330-360W (my educated guess), I would go with a 650W. –  user606723 Nov 23 '11 at 18:28
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Side note 1: I don't think you can use specs as guideline at all: noise level not published (and probably - even measured), PFC can (indirectly) help, but it's not hard rule - bad (loud) fan will be bad anyway

Side note 2: if PSU noise is fan-noise (not only they can buzz in the general case), you can think about replacing fans, and select replacement based on noise-level (there are some silent fans from different vendors)

User-reviews can be starting point in some degree, but mostly it will your homework - find, poweron in shop, listen, make choice. And I see

Ultra-quiet 120mm fan delivers excellent airflow at an exceptionally low noise level by varying fan speed in response to temperature

in PSU description, that makes me think or about the case of warranty or about working near the top-limit for PSU (460GTX eats more than 430W in max mode, AFAIK 550W PSU outlined in specs)

does it help to buy a PSU that has a larger output capacity?

Yes, it can, PSU with additional power from good vendor will produce less noise under your everyday load

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A large percentage of 'high end' PSU's use a 120mm fan for this reason - reduced voltage overhead & increased airflow. 'Enermax' is a name that's been in the business for a long time - i bought an 800W PSU from them over 5 years ago for running multiple hard drives (6 i think) in a power hungry ex-gaming rig (Athlon 1200 Socket A) i used as a home server. I only mention Enermax as their models should be the same whatever country the product is purchased. –  HaydnWVN Nov 23 '11 at 17:04
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