http://www.pcgamer.com/overclocked-core-i9-7980xe-hits-61ghz-and-pulls-1000-watts/

We knew it was only a matter of time before someone doused Intel's flagship Core i9-7980XE (Skylake-X) processor in liquid nitrogen and cranked up the clockspeed, and right on cue, renowned overclocker der8auer posted a video showing the chip running at 6.1GHz.

He was able to push all 18 cores past 6GHz, not just one of them. Not only did this require extreme cooling, der8auer also had to apply a generous portion of thermal paste—both to the CPU die itself, which he exposed by slicing off a section of the integrated heatspreader (IHS), and the surrounding sections of the printed circuit board (PCB). Without doing that, der8auer says he loses about 400MHz under load.