i5-6600k Questions CPU Pll voltage

[AscendanceV]

I built a new rig a while back. Just purchased a new case and Corsair H115i so I could overclock more.

Right now my Intell I5-6600k its OC'd to 4.7 ghz 1.405 vcore. It's passed overnight prime 95 (latest version) test on my 4.7ghz OC. With the new cooler (h115I0 it gets to 79c tops at 4.7ghz.

The other day I accidently set the PLL voltage to +15mv. I was able to get the uncore to 3.7ghz stable with the 4.7ghz core overclock.
I set the PLL voltage back to auto now. I had to drop the uncore to 3.5ghz for it to stabilize the OC.

I have Gigabyte z170xp-sli motherboard.

My question is how the PLL voltage on My motherboard works. I have googled for hours looking but no other board seems to just have a +15mv-+850mv or an auto setting combined.

I don't want to mess with that setting with proper information. So I set it back to auto like I said.

So in short I want to know how many mv I can safely push on my CPU PLL. The safe +mv range.

I'm trying to get a higher uncore because Intel extreme tuner's benchmark show higher numbers the closer it gets to the Cpu's base Ghz.

If you all need more info let me know.

 

[Ecky]

On my Ivy Bridge CPU, undervolting PLL by ~300mv actually improves my stability at high overclocks, presumably because it reduces heat output a little. I would be reluctant to raise it much over stock, but you can probably trust that there's a 50-100mv safety margin built in.

 

[AscendanceV]

Still trying to understand the difference from auto to +15mv. It might of helped stability on my CPU just like your CPU as well.