Overclocking my CPU but want to know if it's safe

[BobTheBrick]

So I've been curious to know if I can oc my CPU, i5 4670k 3.4ghz, to higher than 4.2ghz but I'm not sure if I can through BIOS because my motherboard doesn't let me because it's the H81M-A. How can I overclock a CPU without using the BIOS. And how can I know if it's safe to have it after a certain point such as 4.2+ghz. I have 770 watts from my power supply and vengeance 16gb ram and the Asus gtx 950-OC-2GD5 for my gpu. Thx for anyone who can help!

 

[Curlev]

You should be able to overclock from BIOS: http://www.hardwaresecrets.com/asus-h81m-a-motherboard/6/