dont go behond 80C at any given time! but there's a chance u get to 80C faster using something like AIDA 64 which is the stress testing software than you will while playing a game. AIDA64 really stresses the processor to be used at 100% (all instructions and what not). Even if while playing a game you dont reach 80C but on AIDA u do, i always recommend to follow AIDA64 values and make sure it is stable with it under the correct temps values. If you're OK with the values in AIDA64 you will never have a problem while gaming or doing whatever in your PC. your PC will always be ready to whatever you throw at it.
To be honest with you, OC your CPU for gaming you wont get any BIG advantage in terms of FPS, but what i do recommend is since we bought the CPU and if you can extend the speed for it without touching the VCORE, why not?
specially if you're lucky with the silicone lottery and you can lets say push it to 4.2ghz without touching the voltage
edit: sorry for all the bad English, when i start reading what i wrote i really feel bad, hahaha. i hope you understand it though.
- - - Updated - - -
Let us know your results. Im curious about it
I had mine running at 4.7GHZ with 1.3v and some alterations for the CPU ring as well. It's an old i7 4770K. I have a custom water loop so i was able to push the voltage. with aida running was getting 68C as max temp.
Now i have it running at 4GHz without touch the vcore because i have no need to a 4.7ghz OC... and since i play WoW for so many hours, i want to keep my electrical bill as down as possible. but then again, i have my 2 780 graphic cards running at 1.2ghz with temps of 55C (both on the custom waterloop as well) while playing