Unlock Bios OC prime B250m-K

[Forestay]

Hi I want to overclock my i7 6700k to 4.3 ghz. i know this motherboard isn't capable to oc but my cpu gives good result on low voltages so i won't dig much deeper. in current bios i can't past 4.2 ghz in bios settings. Current bios 1205 here is the bios link: 

BIOS

[Lost_N_BIOS]

I don't understand what you need, you can overclock to 4.2Ghz, but not 4.3Ghz? Is there some limit at entering 43 and only can enter 42?
If yes, what is exact name of that setting and which section of the BIOS are you in when you are setting that.

[Forestay]

I don't understand what you need, you can overclock to 4.2Ghz, but not 4.3Ghz?  Is there some limit at entering 43 and only can enter 42?
If yes, what is exact name of that setting and which section of the BIOS are you in when you are setting that.

I can reach the OC settings in bios on Ai Tweaker page but somehow i cant put anything higher than 42 its always go back to 42 for all cores same happenes in xtu too it wont let me put any number higher than 42.

[Lost_N_BIOS]

Are you trying to set "Per Core" Turbo multipliers higher than the main multiplier? That will cause what you mention. Show me your BIOS page where you are setting this. And the page that shows the "Per core" turbo multipliers. I see no limit set on BIOS, max is 83x

[Forestay]

This is very odd, i set the voltage manually then saved bios restarted and went into bios again this time i was able to change numbers i set 43 by syncing all cores strangely nothing took effect after saving and restarting pc core ratio went back to 42 which is stock.

[Forestay]

ok. now i can change the numbers up to 46 but this really doesn't matter if even bios shows the numbers up to higher than 42 as long as i enter windows i see that cpu still keeps working at base clock speeds. Xtu still locked to max 42 for first core the rest 3 cores only be maxed to 40. nothing can be changed beyond 42 by xtu I guess it really not possible oc on this crappy chipset. looks like more hardware controlled issue.

[Lost_N_BIOS]

4Ghz is stock, 4.2Ghz is max turbo for a single core only, rest will remain at 4Ghz per Intel specifications.
This is per Intel spec not the BIOS, that is how they lock CPU's turbo now I believe, since clocks are so high already.
http://www.cpu-world.com/CPUs/Core_i7/In...6700K.html

Disable Turbo, set 46, then check again using CPU-z. XTU may follow Intel rules, so it may have a set limit per the CPU spec.

[Forestay]

ok, i disabled turbo and set voltage manually to 1.350 this is prior to exiting bios: https://prntscr.com/lsujd6 

This one after restarting: https://prntscr.com/lsuia8

And this one from the cpu-z:  https://prntscr.com/lsujla

As you can see changings won't take effect whatever flip flop i make in bios.

[Lost_N_BIOS]

Looks correct (8-44 multi you set), now put load on CPU single core with CPU-z and the all cores, and let me see image like you showed with CPU-z.

Enable C3 also, maybe that only needs enabled with turbo, I forget. Enable that now for above test, then check without it, then check again with it and turbo enabled.

[Forestay]

OK ' I tested with and without turbo here is a short video: