Xigmatek HDT-S963 Exposed Heatpipe Base Heatsink
 

This is not your average aluminum heatsink with copper heatpipes, but it looks innocent enough from the outside. The Xigmatek HDT-S963 heatsink is a unique thermal solution because the German thermal engineers who designed it, made its three copper heatpipes come in direct contact with the CPU itself. If you take the Xigmatek HDT-S963 in hand and flip it over, you'll see an aluminum base with three long grooves cut into it.

http://www.frostytech.com/articlevie...articleID=2134