Sadly needed exotic cooling
Two of AMD's upcoming second-generation Ryzen processors have already been overclocked to more than 5.8GHz and beyond.
Better overclocking than Skylake
While it might not be interesting for an average consumer, Intel's upcoming 7th generation Core Kaby Lake CPU series might be quite popular with overclockers as it is much better overclocker than Skylake and manages to hit a stable 7GHz overclock.
High factory overclock, insane overclocking ability
High end desktop extravaganza
Might be unlockable as well
Making your hummingbird hum
Using a stock cooler