http://www.silenthardware.de/reviews/ps ... index.html
Yes, that one from every silent PSU manufacturer here in Germany.
Short overview:
Deltatronic Silentium! SPS 420A 290EUR
not audible, heavyweight, only fitting CS601 without cutting.
Engelking AP2-6300SFC-A
not passive
Etasis EFN-300 and
Silverstone SST-ST30NF both 170EUR
not audible 10cm away
Silentmaxx Fanless-Pro 503CPCS 260EUR
auxillary fan, you can choose to enable it or not.
not audible, despite of passive pfc
http://www.silenthardware.de/uploads/pi ... 503w05.jpg looks similar to:
http://forums.silentpcreview.com/viewto ... hlight=pcb
Yesico FL-420 190EUR
audible humming until 1m away
NC-Silence 420 Watt Fanless 150EUR
audible 30cm away
test setup:
AMD Athlon XP 1700+ @ 2600+ (ca. 66W)
ATI Radeon 9800Pro
NB-UltraSilentFan SX2Pro Blacksilence 120mm @ 620Rpm case fan
None showed a exceptional energy efficiency.
A passive PSU reduces the airflow in your PC. If you only need a Panaflo @5V case fan this might be ok. Otherwise buy a low-noise activily cooled PSU. CPU load temperatures got 4-8°C higher compared to a low-noise BeQuiet 400W 1.3 PSU.
Placing the PSU outside the case would be an idea to think about. But whats about electronic noise then?