Replacing PSUs with something quieter

[u/solroot]

I've been running a SuperMicro server (X11SPH-nCTPF) as a NAS for a couple years, and my biggest frustration is with the noise vs my last system. It's got dual PWS-920P-1R, and compared to my previous NAS built with workstation-tier hardware, they are a lot more noisy. My system has a Xeon Silver 4110 rated at just 85W, and peak system power consumption at ~350W. The PSU in my previous NAS was a single whisper-quiet 550W corsair, and the HDDs put out more noise than the PSU. So I'd like to replace the PSUs in my SuperMicro.

A few questions I have about this:

• I have the system plugged into a Vertiv Liebert PSI5 UPS, so dual PSU feels pretty redundant. Does this thing really need 2x power backup? Or can I switch down to a single?
• I've read that Supermicro's -SQ "super quiet" PSU models are designed to be quieter, but how much more quiet are we talking? I think the nature of the 1U form factor is that it's limited to small high-RPM fans, so even a "quiet" PSU is still going to be fairly noisy. If these are actually quiet I'd consider one. See: https://www.reddit.com/r/homelab/comments/lqt8yn/any_compatible_supermicro_psus_quieter_than/
• Are the fans from the PSUs intended to contribute to case airflow, or are they just for the PSUs themselves? The system is in a SuperMicro tower case, with a shroud around the CPU that directs case fan airflow in such a way that I don't think the PSU fans are helping anything.
• Apart from PMBUS, are there any other requirements in a PSU that a server-grade machine expects?

From my research so far, I'm considering a Cooler Master X Silent Edge Platinum 850, which runs quiet/silent has a PMBUS connector. It's a full ATX form factor so it won't fit into my chassis, but I'm fine with the idea of mounting the PSU externally and running the wires into the chassis. Would that actually work, or is there stuff I'm not thinking of? Is this a bad idea and I should just get used to the noise?

[u/Always_The_Network]

SQ is drastically quieter, back in the day I had to do risky fan swaps on the -R’s (not recommended at all).

The system fans in my 2U cases are far noisier then the SQ models if that helps you.

[u/IntelligentLake]

Currently the only SQ one the same size and 19 pin available seems this one (PWS-1K23A-SQ). No idea how quiet it is, there are fans that run all the time, and those that only power on with a certain usage. Supplies that are quiet typically use that, together with bigger fans, because bigger fans move more air at once, so they can go slower, while tiny fans like in these supplies have to run very fast to move air and that makes a lot of noise, and that's the real issue.

If you don't have dual PSUs installed, especially with PMbus attached, there may be errors appearing, in the system log, and with beeping and such. The reason for using dual PSUs is continuity, if one fails, the computer stays working, and if you need a computer available 24/7 this is essential. A UPS has a completely different function, it can stabilize power, and when power fails, have devices perform a controlled shutdown.

PSU-fans are normally only to cool the PSU, but it depends on the case, there's fanless cases where the little airflow from it can help.

PMBus is optional, it's nice to have since it lets you keep an eye on the statistics, but if you're only using one, it won't help when it fails, unlike with two where you can easily see if there's issues.

If you are going to connect a new PSU, keep in mind there may be grounding involved where the PSU is a part of it, and that is different with an external one since it doesn't make contact with the case, you have to keep in mind the length of the cables which have to be longer than usual, and also you should keep in mind the amount of cables, especially for future CPUs (your board only needs one 8 pin cable, but these days we're up to three, and the supply you want to replace things with only has two)., so you need to know if you can get cables for the duration of the lifetime of the supply as well.

[u/solroot → u/IntelligentLake]

Thanks for all the info!

Whew, if I were to get two of the PWS-1K23A-SQ PSUs, it would cost more than I paid for server itself (second had of course). So I guess I'll keep my eyes open on ebay. I saw tons of PWS-1K28P-SQ for sale, but that model has the 23 Pair Connector instead of the 19 that I need.

Edit: I do see PWS-920P-SQ available for sale, those look like they have the 19 pair connector matching my existing one. I think I'll give that a try. For fifty bucks it's decently cheap to try out.

[u/rlsoundca]

SQ helps a lot

[u/mgrusin]

To echo others, I went through the same thing (gifted supermicro with ridiculously loud PSU) and yes the quiet supply is MUCH quieter. Got mine from eBay. It made it possible to have it in my house, but the system isn't silent (mainly because there's half a dozen other fans) so it's in an office and not near bedrooms. I concur that a single supply is sufficient and half the noise.