This message was posted on behalf of Intel Corporation
If you are going to run applications with a single Core, both processors will run at the maximum Turbo Boost speed. In the case of i7-6700k is going to be 4.2 GHz and i7-6700: 4.0GHz
The main differences are the unlock feature of the i7-6700k but it is not fully prepare for Virtualization.
The amount of ram supported and graphics embedded are the same.
It is possible to compare both processors in the chart below: