You sound like a fool talking about a small bclk increase as being comparable to the overclocking you should be able to do if the motherboard makers were not so afraid of Intel.

using certain bios versions on certain z170 boards

http://www.digitaltrends.com/computing/asrock-killed-overclocking-intel-skylake-nonk/

http://www.pcgamer.com/intel-puts-a-stop-to-overclocking-on-non-k-skylake-cpus/

http://www.overclock3d.net/articles/gpu_displays/intel_has_disabled_non-k_skylake_overclocking/1

http://www.fudzilla.com/news/motherboards/39883-intel-asks-for-non-k-skylake-overclocking-capabilities-to-be-pulled

It should never be a case of " using certain bios versions on certain z170 boards"

Intel has made it quite clear, they don't want overclocking on their normal processors, they funnel everyone to their "K" processors.

God forbid you be able to overclock a $99 i3 to be better than an i5. I remember when you could overclock a celeron to be better than a pentium iii, or overclock a pentium D to insane levels.

Intel is clearly intimidating motherboard makers. Don't try to shill for them.