1.2+ kW Silent PSU ideas? (price not an issue)

Hi everyone,

I recently put together a water cooled PC with 2xRadeon 6990 and an Intel i7 2600k. The cooling itself is really quiet as I am using low RPM fans, but the PSU fan is totally ruining my plan for a silent system. It's by far the loudest component in the build. Originally I had a Corsair AX1200, which I replaced with a new unit because of noise problems. The new unit was a bit better, but still not quiet enough. Then I switched to a Nexus RX 1.1k. This one is a bit quieter still, but again far from what I hoped.

So I was wondering if anyone has suggestions for a really silent 1.2+kW PSU. I realize that standard PSUs with such output are bound to be noisy. But what about some custom design, it could even be an external unit? Price is not an issue. I live in Switzerland so it would be better if I can buy something from Europe, but shipping from the US is also an option.

I could not find a suitable off-the-shelf PSU and was thinking of using 3 fanless PSUs (1 for each graphics card and 1 for the rest of the system) ? Do you think that's a good idea? Which brand is most reliable? Do these PSUs need some minimum amount of air flow to be cooled properly or would it be sufficient to just leave them in the open? I don't want to add more fans to the system and ideally I could just place the PSUs outside as they won't fit in the case.

Of course any other suggestions are welcome. I would prefer a single unit of some sort but did not find anything suitable.

8 answers Last reply
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  1. Dont know if these are available to you or if the fan speeds are acceptable but I'll give it a shot.

    Enermax Platimax 1200W is supposed to have a fan speed range of 600-1500RPM.

    Kingwin state a maximum fan speed of 1600RPM for their Lazer Gold 1300 which is based on the Super Flower Golden Green 1300W.

    Silverstone Strider 1500W had its maximum fan speed measured at 1240RPM

    Maybe putting a low speed fan to blow air into the PSU will mean less heat build up so the PSU's own fan doesn't have to spin up as much.
  2. http://www.silentpcreview.com/Recommended_PSUs

    Your idea of "quiet" may be much different from mine. I use ocz, and they're quiet and affordable; I recommend the 135mm fan models.
  3. Do you have any intake fans in your case? If the case is positively pressured a bit it will help the PSU get rid of its heat better. Fanless units do require a minimum airflow as they need to get rid of their heat somehow, they have very specific mounting instructions so that the air flows through them properly, otherwise you risk overheating some of the main transistors.

    One option you have is the new 1kW seasonic platinum unit, it will put out a fair bit less heat than the 1200 W gold units so its fan can run a bit slower, another option would be their 1250 W gold unit but it will probably be about as noisy as the AX1200 was.
  4. Thanks for the replies.

    Just to clarify, my idea of quiet is basically completely silent :D All the fans I have right now, except for the PSU, are 140mm NoiseBlocker XL2 running at max 800 RPM. Combined they are audible but it's more like light wind than the typical fan noise. The PSU however totally ruins the silence.

    I've seen the recommendations at silentpcreview.com and they are all for less powerful PSUs than what I need. I have measured my system use a maximum of 1050W when under heavy load so I need a PSU which can deliver that. My current unit rated at 1.1kW is an absolute minimum and I'd be happier with something a bit more powerful just to be on the safe side.

    Since there is no PSU available that has both a rating of 1.2+ kW and a maximum fan speed of 800 RPM I was looking for alternative solutions. A few less powerful, fanless PSUs would be an option so I will definitely look into the 500W Silverstone model (thanks o1die). The problem is that I would need 3 of them and I can't fit all three in the case. So I will need to put them outside the case. As hunter315 mentioned though these PSU need some air flow to work as expected so that means I would need to design a special case just for the PSUs and some fans to cool them. That's I guess an option but a bit too much effort right now :)

    What about some other, non-traditional solutions? Perhaps an external PSU or something else?
  5. What about replacing the fans from one of those units? A gold rated PSU can't be making that much heat, so even your 800RPM fans should work. Just make sure you are using a PSU that has 120mm fans, or find quiet 135/140MM fans.
  6. I don't know why anyone is recommending the Silverstone Nightjar 500W. It performs worse than Seasonic X series fanless units and the Super Flower Golden King 500W based units yet it is usually more expensive.
  7. @4745454b: I do have a spare Corsair AX1200, maybe I can try modding the fan on that unit. But isn't that a bit dangerous? I mean what if it overheats and catches fire or something, I'm not my insurance company would cover that type of damage :)

    Does anyone have experience with modifying the fan on those high wattage units, what are the temperatures generally like before and after?
  8. Not mod, replace. You don't mod the fan, you remove the old fan and put in a better performing unit. Its not dangerous at all.
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