i7-6700K gone from 4.6GHz to 4.0

[Rezident]

I think my CMOS battery died, I got a new one, but now the CPU (i7-6700K) seems to be running at 4.0 instead of 4.6, it had been stable at 4.6 for a couple of years. I have not changed anything in the BIOS yet, it was already overclocked when I got it, what settings do I need to change in the BIOS to get it back to 4.6?

Motherboard is an ASUS Maximus VIII Ranger.

Thanks.

 

[Rezident]

Yes I think it all went back to default so CPU was down to 4.0.

I tried the inbuild 'Gamers OC Profile' in Extreme Tweaker in the BIOS, and that gets it back up to 4.6GHz but when I stress test it (Prime95 and RealBench) it passes but the Max CPU temp was 90 degrees on one core (in Core Temp)! That seems very hot.

It seems to set the core voltage at 1.44 V.

Any suggestions?

 

[Rezident]

OK I lowered voltage to 1.35 V based on some random googling and it still passes RealBench Stress Test at 4.6GHz (Max Temp: 80). Why on earth would the ASUS default be 1.44 V!? That seems way too high. I'll try a few more stress tests.

What is the max CPU temp we should be aiming for, is it around 80C?