750g copper cooler

Massive copper CPU coolers do exist. In fact, this particular one designed for actively-cooled servers can be found on the cheap from eBay. Granted, it is not particularly convection-friendly, but thanks to its sheer size (and weight!) the 35W i3-4160T is kept at around 40°C most of the time. Special thanks to Tony Bonnin for these pictures and awesome build.