New pc crashes while playing

[mazTart]

Hey guys I just built a new pc last month and I've been having some issues.
Sometime when i play (cs go for example) the game crashes. A black screen pops up and a green frame pops up for a split second and then it creates a buzzing sound out of the speakers.
This happened with ac revelations but I saw that limiting the fps to 60 stopped it, i tried that on cs too but didnt work.
The crashes still occur after I disable the gpu overclock. CPU was stress tested for 30mins without problems. Temperatures are all very stable.Crash occurs randomly usually 20mins-ish in?
Specs-
I5 6600k 4.3ghz overclock
rx 480 1290 mhz and 2055mhz(memory) overclock
z170m mortar
hyper evo 212x
Id really appreciate any help and dont hesitate to ask for more information if i missed out anything.

 

[burgessanthony]

Unstable CPU oveckoxk is first guess. Add some volts.

 

[mazTart]

Unstable CPU oveckoxk is first guess. Add some volts.

The cpu has plenty of voltage infact most guides say that it will easily hit 4.4ghz without changing anything but the core clock.I cant ever get a 4.4ghz+ overclock without crashing though no matter what voltage i set.I had to give it more volts just to reach 4.3ghz stable thats another problem though.

 

[mazTart]

bump?

 

[mazTart]

Unstable CPU oveckoxk is first guess. Add some volts.

I just checked the BIOS while booting and for some reason the CPU wasnt overclocked so it cant be from the CPU