Overclocker Cafe pipped us at the post on this one... We were shooting for an exclusive of the new Volcano 9 cooler from Thermaltake except they managed to get their review out a couple days before us - Our review will be up before much longer!
The base of the Volcano 9 measures 10mm thick. As we noted above, in the center of the base is a circular copper insert. Copper has a higher thermal capacity than aluminum but it doesn't dissipate the heat as quickly as aluminum does. That is why you see so many performance oriented heatsinks being a mix of copper and aluminum in their construction. The copper insert was smooth and flush to our eye and finger. We placed it onto a piece of stained glass to check for any imperfections. None were found.More information at Overclocker Cafe.