The problem with most socket 370 and 462 era hardware being loud is that the CPU fan is fed 12V all the time and not throttled in any way.
The easiest way to solve the loudness issue, at least for most socket 370 hardware, is to simply remove the grounding (usually black) pin on the fan and plug it into a 5V line, essentially making the fan run at 7V (12V - 5V = 7V difference). Just beware that there may be boards that check for CPU fan tachometer (RPM) output... so with the above suggested method, the tachometer usually stops working on most fans.
The second easiest method is to remove the positive (12V) wire from the fan connector and use a resistor in series to lower the voltage. With this method, the fan tachometer output will still work... and also, depending on what resistance you end up using for your resistance (20 to 100 Ohms tends to be the common range to get most fans quiet enough), you are free to set how loud you want your fan to be (at the expense of worse cooling and higher CPU temperatures.) Depending on how large the CPU heatsink is, one can make a nearly whisper-quiet rig or not so much. For the most part, stock Intel P3 heatsinks can have their fans run at half the voltage (6V) and still run plenty cool, even under 100% CPU load.
Now, as for socket 462, particularly the CPUs being quite a bit warmer than P3's, the above suggested ideas may not be achievable. But again, it all depends on how large the heatsink and fan is and also the CPU TDP. Low CPU TDP combined with a big-sized heatisink should allow for a good fan speed reduction (and this reduction in noise.)
