Questions regarding Vcore vs Vcore Offset on Haswell + Uncore Ratio

Hans Power · February 17, 2019

I'm currently overclocking my Haswell I5 4690k on a Gigabyte GA-Z97MX-Gaming 5 and for good enough temps on stresstesting I settled on 4.3Ghz with a VCore Offset of +0.060v which adds up to 1.224v according to HWinfo64.

That seems to be stable and cool enough (at 88°C peak) with Realbench 2.56 which even uses AVX as far as I understand. But there's still some stuff I'd like to know to get the most out of my Hardware.

1) Is there a benefit of using a static Vcore instead of a Vcore Offset (specifically on Z97 + Haswell)? Also, with energy cost in mind (which is rather expensive in germany) - how much energy savings can I expect when the system is idling with a Vcore offset and all the other power saving features intact compared to static vcore and/or CPU clocks?

2) I'm currently experimenting with Uncore Ratio and I'm having trouble to get a stable system when I raise Uncore Ratio to 4.3 or 4.2 Ghz. 4.0 seems to be stable (for ~20 min so far) without any further adjustments.

First: Is it actually worth it performance wise for games and

second: What would I have to do to get a stable Uncore Ratio working at 4.3 or 4.2 Ghz? I tried raising the Vcore Offset to 0.080v but that raises the temps to up to 100°C (with AVX) on my not so beefy aircooler and didn't help with stability - at least not enough.