if the CPU is causing crashing then reset the overclock back to factory speeds, don't want to risk killing an unstable CPU. If i were you, i would do it manually in the BIOS and go up in small increments, for example do a clock of 4.2 with a core voltage of +0.50v and if that posts and lasts for 10 mins in Aida64 cpu stress test then try 4.3/4 with the same voltage, if it doesn't pass then put up the core voltage up to the next one and try again.
HOWEVER, if you aren't 100% sure then please go watch as many skylake overclocking guides as possible. also bear this in mind; not every CPU is made the same, while one 6700K may be fine at reaching 4.6GHz and a low increase in voltage doesn't mean that yours will too. For example, my 5820K reached 4.5GHz at a small bump in voltage, however I know someone who's 5820K that just wasn't happy at 4.5 and derped out.

As for the GPU, as long as temps are fine and it doesn't crash then sure.

thank you for helping i had to lower both my overclocks due to crashes my gpu right now is at 1488mhz boost clock and my memory is still at 4000mhz with 10v. thought i had that stable because it lasted a hour on the heaven benchmark but crashed on vally after 10 min so i put voltage to 15 now it seems stable on vally. is 15v safe? also i put my gpu overclock down to 4.59mhz and ran real bench and it was good for over a hour and completed several runs but then crashed is that overclock still okay or should i dial it back again? because i dont think ill ever stress the cpu that much accept for when i am running real bench

if it crashes after any time period, then dial it back. some people like to test for 24 hours of full load to make sure.
also it wouldn't be 15v... that is more than a car battery.

I meant i put the voltage bar up by 15 on msi afterburner. i put the over clock on my cpu down again to 4.4mhz is that still a decent overclock im stress testing it now to make sure its safe. also i figured out why i was having so much trouble getting a stable overclock on my gpu. its because for some reason even at stock overclock my boost clock was 1418mhz even tho its only supposed to be 1367mhz meaning its over 50mhz faster then normal so i was seeing all these people add 100mhz or more but that would mean there boost clock would only be around 1467mhz i would try to add 100mhz and my overclock would be 1518mhz which would crash my card. so i added a much more realistic 70mhz to core clock and making it 1488mhz and i added 300mhz to my memory making it 3800mhz and now even without any voltage my cards stable.

Nvidia cards have a feature called GPU Boost 2.0 which bases off of the temperature of the card and will overclock accordingly, for example my 970 is rated at 1387Mhz but GPU boost takes it to 1535Mhz on it's own.

well then idk why but my cards gpu boost 2.0 seems to not be working right because is it possible a setting is stopping it from working?