How hot should I let my i5-3570K get?

Just upgraded this weekend and am having a blast with my games.

Replaced Intel's stock paste with Arctic Silver 5, and I'm getting great temps with the stock HSF.

Tried my hand at some overclocking, and set All Cores to a 42 multi. Left voltage on Auto.

None of my games stress the CPU enough to get it above 70C even overclocked except Crysis 3 - which I left for an hour staring at a sea of grass as a benchmark. Got to 79C, and this is the most intense thing I will do with my CPU, probably ever.

I would like to try allowing it to turbo up to 4.5GHz on one core, with steps down by 100MHz when adding cores.

My only concern is the voltage has already hit 1.221v where I'm at now on Auto. I know I'm asking for a lot more heat, but in my case it will be very limited to intense gaming moments.

Checking temps and such with HWMonitor, btw. Rig in sig.
 
80c is your thermal limit, if your going above, you need better cooling.

what cpu cooler do you have?

if your going for a higher overclock and your vcore is getting near 1.40v, then you would like to be under 70-75c because of the voltage spikes and small heat spikes that you cannot see.