I read on Reddit that during the first stable OC of 5.3GHz, the entire system swallowed 1.2kW of power so I would assume increasing to 6GHz would put it in the region north of 1.5kW.
Comparing that to Intel's 28 Core 5GHz OC, that needed 1kW just for the CPU and a further 1kW for the cooler. That's 2kW discounting the rest of the system which comparing it to the ThreadRipper CPU is just insane
could be related to DX12 implementation, i know AMD did a fair bit of work regarding multi threaded command buffering so maybe that is bearing fruit with the massive number of available threads