did i get bad silicon?

[Baumy15]

i got a new pc with a 6700k and over the last week have been overclocking and currently i have it running at 4.7Ghz at 1.28v (1.312v under load) i have found that it will run at 4.8, 4.9 and 5Ghz at voltages 1.34, 1.39 and 1.425v but isnt stable at those voltages (have tried 4.8Ghz at 1.4V and still crashes after a few hours) is there any system voltages or other tweaks i can try? i have an asus z170i pro gaming and a h110, im new to asus bioses.

thanks

 

[mrmez]

* Overclocking not guaranteed.

 

[Baumy15]

* Overclocking not guaranteed.

I know that, but are there any system voltages i can up? On my 4690k changing the input voltage and the pch boltage made the chip stable at a lower voltage wondering if there is anything like that on z170/skylake