I'm so glad you asked, since I just spent all weekend trying to get my Duron system as quiet as possible. Here is what I did:
1) get an Enermax PSU
2) get a Silverado Noisecontrol !!
3) get lots of quiet big fans
4) get a MacPower DigiDoc 5
5) get a big case.. HUGE if possible
6) get "isomo" or another insulating foam
Okay , the Enermax PSU's are supposed to be the quietest psu's on the market. I got a 350w that with a thermo controlled fan. Now, there is a known issue that I encountered with these PSU's; the thermal probe is not well positioned in the airflow, resulting in a PSU thats only quiet for about 10". Enermax is sending out modified psu casings to solve the issue, I'm still waiting for mine..
The Silverado is a MUST HAVE. Its dead quiet, and cools pretty well, depending on what cables you use. It comes with 6v,8v and 10v cables. Depending on your requirements, you select a cable. 10v is supposed to handle 1.4's just fine, and of course you can simply supply default 12v to get "ultra" cooling performance. Please note the SIlverado requires TWO fan headers, since there 2 fans on the thing (the cables offer 2 fan headers each).
Next thing I did, was install the DigiDoc 5. This is one cool gadget. Not required, but real fun, and also slightly usefull. it fits into a 5,25" driver bay and offers 8 fan headers, up to 8 thermal probes, and a groovy display. The idea is to place a probe, attach a fan, and define a treshhold temperature above which the degignated fan will be actived.
I attached both my Silverado fans to the digidoc, placed a thermal sensor on the cpu, and configured the digidoc to start fan 1 (8v) above 40° and fan 2 (6v) above 50°. I know this is rather hot for a Duron @933, but the idea was to have a QUIET system (both fans connected all the time @6v gives me 37° iddle 42 max).
I installed all the other fans, and configured them as such:
1) 100mm exhaust fan, 8v, >30 case temp
2) 80mm HD fans, 6v > 35 HD temp
3) 100mm inlet fan, 6v > 33 case temp
Since Im still waiting for the PSU mod, I disconnected the rear fan of the PSU, plugged it into my DigiDoc, placed a sensor on the cooling element,and configured it to run once the PSU got > 40. Disadvantage is that you loose variable speed, its either on or off, but connected at 8v, its still quiet when its on (rarely).
Last thing I did was put isomo (styrofoam ? not sure how you say that in English) around my drive cage, and on the inside of the case panels.
The result ? Silence.. and I really mean its almost as silent as my portable. When I really stress the thing (like running defrag and Prime95 together for an hour) most fans kick in from time to time (CPU and rear exhaust fan all the time), but the DigiDoc is so fast, the fans dont even spin up to 100% speed before the temps are lowered below the treshold, and the the fans are killed again. You hardly notice this process.
My only wish for the Digidoc was that it would allow fan speed control, by adjusting the voltage... like setting a minimum tresh hold temperature (would result in 6v) and a maximum (full 12v). Maybe the next version ?
Anyway, good luck, and let me know I can be of any further assistance
---- Owner of the only Dell computer with an AMD chip