Issues overclocking i5 6600k

[cd228]

Hello Overclockers.

I have an issue with my overclocking and have run into a problem. I have seen other threads which have been solved but their solutions has not worked with mine.
Well, I have an i5 6600k cooled by an evo 212. With the core volts set to 1.2 it is stable at 4,2Ghz. I can also make it run stable at 4.3Ghz if I increase to 1.24 volts. If I go for 4.4Ghz I need to increase voltage to 1.28 and this is here the odd thing starts. The multiplier starts fluctuating between 44 and 42 (effectively 4.4 and 4.2ghz). If I further increase voltage to 1.30 the fluctuation increases to be between 44 and 38. If I dial back the overclock to 4.3Ghz and let the volts be at 1.28 it is still unstable and fluctuates between 43 and 42.

I have tried disabling all kinds of power saving functions, speedstep, etc. I have also made sure that no power settings in windows has been enabled. The temperatures are max 62 degrees, so I don't imagine it is thermal throttling. The TDP at 95w, only about 82 watts are used, so I don't imagine that is the issue either.
The problem seem to occur independently of the frequency but solely dependent on the voltage.

I am satisfied with my 4.3ghz overclock, but I am simply curious to learn what is happening:).
 

[hconverse02]

Just leave it at 4.2 if you are worried btw

[cd228]

Well, I'm not worried. Simply curious to know if I miss something as there seems to be more potential in the chip:)

Normally you increase voltage to gain stability, but here it seems that increasing the voltage makes it more unstable.

[AI3X]

I have an i5 6600k - Cryorig c7 - 4.8GHz @ 1.3 V, maybe try increasing the voltage a bit? Up to 1.35 should be safe. I left my multiplier at default and then increased the base clock on my overclock. Your cpu cooler should be fine and temps are probably not the issue, try doing a CMOS and then updating your mobo bios.