Reports indicate a lot of 8700K samples easily hit 5GHz with decent cooling and now there's news that an extreme overclocker performed an over 100% OC on the 8700K!
Overclocker Kovan Yang uploaded his scores to HWBOT. With the help of LN2 cooling, he managed to hit 7405.12MHz on the Core i7-8700K. That's an overclock of 100.14 percent, with a bus speed of 101.44MHz and a multiplier of 73.
This feat was achieved on the MSI Z370 Godlike Gaming motherboard.