unfortunately the unlocked(K and X) chips are the costliest in their segments specifically due to their overclocking capabilities...
so are the z170 baords due to the same reason...bcoz that is the only board whr u can OC...
i ll still say, that its not worth the effort to OC a locked chip...there wont be any huge performance enhancement that u can tap out of it, compared to a unlocked chip...but then again, its ur decision...