Several companies make quiet power supplies:
The holy grail, of course, is a completely silent, fanless power supply. TK Power makes at least one fanless model (the TK230-1U), although it's not advertised on their web site. Unfortunately, it may not supply enough power for many systems (~150W). That's plenty for an C3 system (mine probably peaks at considerably less than 65W), but not for an Athlon (where the CPU itself can suck 65W). I ordered one of these straight from TK, had a lot of problems actually getting them to send me the unit, but eventually got it. However, to address some of those problems, TK now sells through a distributor. Hopefully, this will make getting one of their units less painful.
I cannot evaluate how well the PSU performs electrically without either risk of damaging it or some schematics. However, the actual power supply appears well built, and cleverly designed from a thermal standpoint. All the components that run warm are thermally coupled to the case, which is made of 1/8 inch metal (probably aluminum). Since it was still a bit warmer than I liked (though well within thermal limits of power components), I stuck a giant heat sink on it, and now it's a pleasant warm. Contact: Orion Industries, at (603)894-4242, and ask about TK's line of fanless ATX power supplies.
The German RSG makes a fanless 130 watt AT power supply, though it's rather expensive (on the order of $150). I just got a note from a reader that they are also working on an ATX version (2002):
I just spoke to a guy named Wiederspahn from RSG and he told me they are currently developing a fanless ATX pentiun 4 compatible 300W power supply, It will be avalable somewhere this summer.
Several people have had success running normal ATX power supplies, with the fan ripped out. If you value data integrity, I'd caution against this, as if the right parts of the PSU burn out, you may find a higher voltage pumped into your hard disk, motherboard and CPU on the 5V pin or similar problems. Several people have told me that they don't value data integrity (they were using the machine as a cheap router, so if it blew out, not much harm done). If you get a significantly overrated PSU, the likelyhood of this happening is pretty low. If you really want to risk it, at least stick the fan on a heat-activated switch (All Electronics periodically stocks some for about a buck).
When going fanless, make sure the rest of the system has adequate cooling. Either run open-case, or find some alternative way to prevent hot air from getting trapped inside the machine. You may also want to run a burn-in test to see how hot the chips on your motherboard and cards get, and stick additional heatsinking on the ones that run warm (heatsinks can often be found cheap on surplus electronics web sites).
On my personal power supply, before getting the TK Power, I took of the original fan, and crimped on a quieter fan from Panasonic. This made a significant difference, but was still a bit noisier than I wanted.
Copyright © 2000. 2001. Piotr F. Mitros. Questions? Feedback on the site? Feel free to contact me.