Heatpipes are everything for this colossus. The heatsink fitted to the CPU is barely any larger than the kind you'd see on GPU RAM. It works, though, with most of the heat being dragged up to a larger block hovering above with a 120mm fan bolted to its top.
You can fit a second, but we're unconvinced it'd make a difference. It's a fine construct, but given the fan size we'd like it to be slightly quieter.