i5 6600k 4.5ghz at 1.2v stable? What am I missing?

So after doing some testing with different multipliers and voltages, I'm at 4.5ghz and 1.2v. I read that to archive 4.5ghz you need like 1.3+ volts. How is this possible? What's the deal?

I did a 20 min stress using AIDA64, 10 mins test using ROG CPU-Z and 1 hour gaming (R6 Siege) and everthing looks normal.

I have a Hyper 212 LED and my temps during stress were 60c with 69c spikes. While gaming was around 47-58c.