You know when FrostyTech.com does one of its heatsink reviews, it's worth checking out. The FrostyTech gang have just posted a report on the Arctic Cooling Alpine64 heatsink, and another review on the older Coolermaster Hyper48.
"The Alpine 64 suspends its 2000RPM fan on four dual axial
rubber vibration absorbing posts. The general purpose of which is to prevent fan
motor vibrations from transferring to other areas of the computer chassis which
could cause noise. The whole package weighs in at just 486 grams, and
judging by recent information the Arctic Cooling Alpine 64 should even be compatible with AMD socket AM2 heatsink retention frames..."