I'm looking for a high-quality power supply that is no longer than 140 mm and preferably rated at least 80 PLUS Gold. I'd like something very quiet, or ideally fanless when possible, and would prefer to stay under 750 W. There don't seem to be many units that meet these requirements, so I'd appreciate recommendations and advice on which models are genuinely quiet.
3 Answers
A fanless Seasonic model may fit what you want, although you’ll need to confirm its exact dimensions and availability. Modern SFX power supplies are another possibility; the Corsair SF1000 is well regarded, but it is much more power than you need and the included cables may be too short for a larger case. The Thermaltake PF3 series could also be worth checking.
Look at Cybenetics noise certifications and test results rather than relying only on the manufacturer’s claims. A power supply can be completely silent whenever its fan-stop mode is active, but some models only stop the fan at idle while others remain fanless under much higher loads. Coil whine is separate from fan noise and is unpredictable from one unit to another.
There are quite a few models that meet the size, efficiency, and wattage requirements, but noise levels vary. The Montech Century II Gold 550W is one option worth investigating. I’d also check an independent PSU tier list before buying, since efficiency certification alone doesn’t tell you much about build quality or acoustics.
Do you know whether the Century II is actually quiet? I haven’t been able to find much reliable information about its noise levels.

Would a fanless unit make the inside of the case warmer and force the other components to run their fans more often?