Which PSU is best for a silent SFF workstation build?

Question

Look I've been building PCs for over ten years now so I thought I knew what I was doing but this whole SFF transition is kicking my ass. I'm trying to downsize my workstation because I moved into a smaller studio space in Portland and I'm doing way more high-fidelity audio recording now. Problem is I bought an SFX unit that promised silent operation but the coil whine is literally audible on my condenser mic and the fan curve is all over the place. It's driving me insane. I have a massive project due this Friday and I can't finish the mix with this buzzing in my ear. Budget isn't really the issue I'm fine dropping $200 or whatever on something that actually stays quiet under load. Is the SF750 still the go-to for this or am I better off looking at those newer ATX 3.0 units from Asus or maybe even a fanless Seasonic if I can cram it in there? I need something with a rock solid zero RPM mode that wont click every time I launch a render. Which PSU is actually the best for a silent SFF workstation build?...

Aoe · Accepted Answer

Coil whine is the worst when youre tracking audio. I would suggest sticking with the Corsair SF750 750W 80 Plus Platinum because its zero-RPM mode stays passive up to 300W and its notoriously quiet.

Be careful with SFX-L units as they might choke in tight cases.

Check the fan curve data for newer ATX 3.0 models; some ramp up to 30dB instantly. Make sure you avoid units with cheap sleeve bearing fans tho.

George Fish · Answer

Regarding what #3 said about "Ok adding this to my list of things..." - definitely check out SFX-L units! I agree with the bigger fan approach because it is way safer for heat management during heavy renders. I once had a unit get dangerously hot and it basically scarred me for life tho! Now I love my Cooler Master V1100 SFX Platinum 1100W. It stays totally silent! TL;DR: Over-spec your wattage to stay in the zero-RPM zone longer for silence and safety.

ydteysuenn · Answer

If you can fit an SFX-L unit in your chassis, you should definitely consider the ASUS ROG Loki 850W Platinum SFX-L ATX 3.0 instead of standard SFX. The primary reason is the fan size. Standard SFX is limited to 92mm fans that have to spin faster to move air, while SFX-L fits a 120mm fan. Physics basically dictates that a larger fan is gonna be quieter at the same airflow levels. Another thing to look at is the Cybenetics noise certificate rather than just 80 Plus. You want something with a Lambda A+ rating. The Loki units are remarkably quiet and the ATX 3.0 spec means they handle those transient spikes better without triggering the fan to jump to max speed. Just make sure your case doesnt have a hard cutoff at 100mm for the PSU length or you wont be able to plug in your cables.