6600k OC wall - unlucky in silicon lottery or something else?

[BlackHoleBox]

I've been running this 6600k at 4ghz at stock voltage (1.125) since I got it and it's been completely stable, including a few days of Prime95 with no issues.

Recently I decided to see how far it could go, but I was done sooner than I expected as it runs completely stable at 4.2 and 1.130v, but 4.3 at any voltage up to 1.2 crashes just opening a browser.

Is it just a case of not enough voltage or something else? Even with water, I'm hesitant to go over 1.2.

Gigabyte z170x-gaming7
i5 6600k
4x4GB GSkill TridentZ 3000
Corsair HX1000i

 

[photonboy]

"That being said, we weren’t able to see many gains from pushing the Base Clock. Increasing it by even a few MHz led to instability and crashes until we started boosting the CPU voltage. We had more luck by increasing the multiplier, easily pushing the i5-6600K to 4.5GHz at maximum Turbo speeds without needing to adjust voltages. This gave a significant boost in our multimedia benchmarks, producing a fantastic overall score of 146. We pushed the chip further to 4.7GHz for a slightly faster 148 total, but we had to increase voltages to beyond 1.35v to keep the chip stable."

http://www.expertreviews.co.uk/pcs/cpus/1403688/intel-core-i5-6600k-skylake-review/page/0/1

Based on what you've said, it's likely you could go a little higher with more voltage. It will wear out your CPU but how fast is difficult to determine. I never recommend pushing it to the limit because that leaves little headroom for when the chip does degrade (and all chips do).

Multipler: I'm not familiar with overclocking on all platforms, but on my older Z77 setup I can change the MULTIPLIERS only if I want. For example, for "4-core" usage I am stable at 4.2GHz so the multiplier is set to "42" instead of the default which was probably about 37.

You may be able to do something similar. I recommend at least 200MHz lower than where you lose stability.

 

[chenuki]

To have much success you gotta be willing to take some calculated risks.

Some useful pieces of info:
1) Intel's spec max for Skylake/Kaby is 1.5v
2) siliconlottery regularly bench their i5's at 1.44v
3) Obvious diminishing returns past 1.4v

From that you get the upper limit and a typical OC limit with a safety margin. 1.5v does not guarantee the chip will die and 1.125v doesn't mean your chip will last forever. It's about finding a balance that your heart's comfortable with.

My experience with Skylake/Kaby is anything around 1.4v with good temps is perfectly alright for daily use. I suggest bumping Vcore to 1.44 and see what your chip will POST at. That should give you an idea of your lottery luck. Then back off a few steps and test stability, temp etc. Results may surprise you without having taken much risk.

 

[mrobscura]

you simply need more voltage than 1.2 for 4.3ghz. while every chip is different, my 6600k, for example, ran at 4.4ghz with around 1.31v.