There is a bit of controversy on the web at the moment as some info appeared on the web regarding Intel's upcoming Skylake lineup. The information claims the existence of a Core i7-6700K and Core i5-6600K, runing up-to 4.2 GHz.
Now here's the thing, we stated controversy on the first paragraph as the source is a website called PCFrm and they have no track record whatsoever in regard to validity.
The Core i7 6700K would be a 4.0 Ghz processor that can boost to 4.2 GHz, the 6600K model would do 3.5/3.9 GHz.
- Core i7 6700K
4 cores and Hyper-Threading, 4.0GHz frequency, 4.20GHz maximum Turbo Boost frequency, 8MB last-level cache, dual-channel DDR3/DDR4 memory controller with 1600MHz or 2133MHz support, 95W TDP, Intel HD Graphics 5000-series integrated graphics core, LGA1151 packaging
- Core i5 6600K
4 cores, 3.50GHz frequency, 3.90GHz maximum Turbo Boost frequency, 6MB last-level cache, dual-channel DDR3/DDR4 memory controller with 1600MHz or 2133MHz support, 95W TDP, Intel HD Graphics 5000-series integrated graphics core, LGA1151 packaging;
Skylake is the codename used by Intel for the 14nm processor microarchitecture under development and due to launch in 2015 as the successor to the Broadwell architecture. Intel 14nm Skylake processors will feature PCIe gen 4, DDR4 Memory and SATA Express support. Now anybody can type up this stuff so yeah, take it with a big grain of salt.