I have owned the following "quiet" power supplies over the last year:
- Fortron 300 120mm
- Fortron 350 120mm adjustable
- Seasonic Super Tornado 300 120mm
Read through this forum and you'll find many other people complaining about the same thing. Power supply fans, from every vendor, that ramp up to comical speeds under not-so-large loads in the neighborhood of 150w. This seems to be a common industry practice, probably due to overzealous safety concerns by manufacturers.
Subsequently, I have completely given up on expecting any stock as-purchased power supply to be quiet without replacing and/or undervolting the fan. I recently purchased the Zalman ZM300A-APF, and right after opening the package, ripped it open and swapped out the default 80mm fan for a Panaflo L1A.
Silence at last.. even under a "massive" 150w load. Is that so much to ask? Evidently it is.
* From my dual athlon 2500+ server (undervolted) with two folding instances, 4 hdds, and 2 scsi cd-rs. Yep, merely 150w according to the kill-a-watt.