How quiet is quiet — new psu?

John J. Williamson · 16 Apr 2021 at 01:46

Evening all,
I have one of OCUK’s budget builds in a Kolink sanctuary cube case with, I think, Kolink’s ‘80 plus bronze’ PSU. Not sure the wattage.

The system is great but I use it for multimedia a lot and am questing to quieten it a bit. I’ve put a be quiet CPU cooler and case fans in there and they are running nice and slowly. The majority of the noise seems to be from the PSU now, based on listening at different parts of the case.

my question is really, can I expect to find a PSU that is as quiet as the pure wings 2 fans I have just installed? How quiet should I be aiming for? Inaudible at a few metres away, or is that impossible given that the Kolink case has vents all over (eg the top is essentially all ‘grille’ rather than solid).

Any tips appreciated.

Hotwired · 16 Apr 2021 at 02:04

You can if you pay for it, get a psu which is either fully passive or a psu which has enough passive cooling to shut off the fan below certain temps which is a lot easier to do than fully passive.

Ah ocuk has a subsection for semi passive psus: https://www.overclockers.co.uk/pc-components/power-supplies/semi-passive

Rroff · 16 Apr 2021 at 02:49

Quite a few of the higher end PSUs as above will run fully passive up to a certain load level - IIRC mine doesn't spin the fan up until around 250 watt draw so on the desktop and under light to moderate application usage it is silent or at least very quiet.

John J. Williamson · 18 Apr 2021 at 09:41

thanks both. went for a Corsair rm650x and it’s amazing the difference. Thumbs up fr that and for the be quiet case fans and cpu cooler.

Grim5 · 19 Apr 2021 at 01:59

Rroff said:
Quite a few of the higher end PSUs as above will run fully passive up to a certain load level - IIRC mine doesn't spin the fan up until around 250 watt draw so on the desktop and under light to moderate application usage it is silent or at least very quiet.

Mine starts spinning at 450w, but even once it's spinning I can't hear it - once they start spinning they still operate at a low rpm

Cooler running · 20 Apr 2021 at 21:31

Hotwired said:
You can if you pay for it, get a psu which is either fully passive or a psu which has enough passive cooling to shut off the fan below certain temps which is a lot easier to do than fully passive.

Ah ocuk has a subsection for semi passive psus: https://www.overclockers.co.uk/pc-components/power-supplies/semi-passive

from what i can see there arn't any full passive psu's in stock anymore, the last one was one of these:
https://www.overclockers.co.uk/silv...lar-fanless-sfx-l-power-supply-ca-44f-sv.html

Hotwired · 20 Apr 2021 at 21:34

Cooler running said:
From what I can see there arn't any full passive PSU's in stock anymore, the last one was one of these:
https://www.overclockers.co.uk/silv...lar-fanless-sfx-l-power-supply-ca-44f-sv.html

Ye well full passive is a bit naff anyway because of the physics of it. The modern approach of semi passive gives you silence for a decent range of use then starts wafting air which means it can safely be a much higher wattage.

Meddling-Monk · 21 Apr 2021 at 18:58

Hotwired said:
Ye well full passive is a bit naff anyway because of the physics of it. The modern approach of semi passive gives you silence for a decent range of use then starts wafting air which means it can safely be a much higher wattage.

Kinda depends on what you're doing I guess.

Most of the decent range (no fan) on Semi-Passive PSUs requires that you purchase the most expensive PSU's on the market for the highest Power so their no fan range is big enough (AX1600i, fan starts at 600W usage), which is near or more than twice as much as the leading fanless PSU (700W). Price comparison done on a current price for semi-passive AX1600i vs price I paid for my 700W fanless.

But the issue is, if you're using one of the higher medium GPU's these days (3080 or 6800) with their spikes of 500W+ added onto what the rest of the system using in a game, you're likely looking at over 600W easily in spikes that'll cause even the high end semi-passive PSUs to spin up their fans up and down as the power draw happens. The Fanless will remain fully silent in this situation so long as total power draw isn't above what its rated at.

If you game at night and don't want to wake light sleepers up, fanless is better if you have a more recent GPU. If you're using an older GPU with a much lower power draw, then going with the semi-passive approach is best so long as the price is right.

Drumroll · 29 Apr 2021 at 22:10

Under load, I'm quite sure the GPU and CPU fans would be louder than any good qualit PSU's fan.
Had issues in the past with EVGA fan, but only happened with he fan vertically, as many cases now do. As intake at the bottom, or too, no noise.
And isn't all about power. Returned a 1000W Corsair platinum, very loud coil whine. Using a 850W Seasonic Platinum, decided to keep the fan on, can't hear it and no coil whine.

OverDrive · 1 May 2021 at 09:09

The Seasonic Focus GX-850 PSU I have is silent (fan off most of the time). When the fan does come on (rarely) you literally have to put your ear right next to it to hear it, and even then it’s so quiet you can only just about hear it.

As said above, GPU and CPU cooler fans will render any noise from a good PSU insignificant anyway.