The i7 6700 runs at base clock of 3.4 and has a turbo to 4 and it comes with a stock cooler and the mobo H170 will down clock the Ram to 2133 so no need for high BW memory
The i7 6700K runs at a base clock of 4 with a turbo to 4.2 it don't come with a cooler so you need one , the reason I went with high BW memory with this setup is that it will help on min fps in games 2 to 3 % and its helps with OCing your cpu and some Editing software and other stuff in real world we are talking about a few secs
both are 4 cores with HT as far as gaming goes with the non K cpu you are able it fit in a gtx 1070 vs gtx 1060 witch will be a better boost in FPS then going with the i7 6700k that you can OC