I bought a Rackable Systems 2U Dual Opteron 2214 HE server for my VMWare ESXi playground. For $125 it was a steal. I brought it home to find out the sound was defeaning. Not satisfied with the level of noise especially considering the Master Bedroom is 20-30 feet away from my Office. Opening the case I found a 1U 70mm "leafblower" heatsink/fan on the front CPU and a 2U 60mm "leafblower" heatsink/fan on the back CPU. Disconnecting those 2 fans along with the rear 3 80mm fans it was much better, but still had a ridiculously loud noise. Looking at the PSU, it has a 40mm fan on the front. Noting the motherboard had standard ATX connections, I hooked up my spare Antec EarthWatt 500w power supply. Nearly silent. Now onto the CPUs. I attempted to take the Dynatron 1U heatsink's fan off, but was unable to, the screws are pretty much stuck. The rear 2U fan however was easy to pull off, put a 70mm fan I took off a spare AMD AM3 Stock Heatsink. Booting up to the bios and monitoring the temperatures, the 2U with the new fan was hovering around 38'C, while the 1U was hovering at 65'C. Knowing that was under no load, I would need to do something. Thus the ultra ghetto 120mm blowing air onto the 1U:
While not the prettiest sight, it is very quiet. A little bit more than my 4U SAN sitting below it, but no where near the 50+ decibels it was before.