Extremely high Vcore voltage (4 V) on Asus Prime Z270-K with 7700K

[dirtyred]

Yesterday I was doing some OC stress testing my 7700K with Realbench. I'm using AVX offset since my cooling is not (yet, soon getting a better one) enough to handle high multipliers and voltages. Applied a multiplier of 47 and AVX offset 3 with an adaptive voltage of 1.25 V, no offset. In RealBench since it's using AVX the CPU was running on 4.4 GHz @ around 1.152 Vcore, occasionally jumping to 1.6 V. Since it wasn't stable I raised the LLC level from 3 to 4 (or from 4 to 5, can't remember exactly but definetly one of those). IA AD/DC load line is set to 0.01. Pretty much everything is set as Raja@ASUS wrote in the Kaby Lake overclocking guide. Now my Vcore was around 1.6 V with occasional spikes of 1.8 V but still unstable. Under non-AVX load the Vcore was pretty stable at 1.248 V.

Did not want to raise the Vcore above 1.25 V since above it my CPU is reaching 80-85 degrees under RealBench. So I decided to play around with the offset. Lowered the Vcore to 1.215 V and applied an offset voltage of 0.04 V resulting in Total adaptive mode CPU core voltage of 1.255 V. Rebooted, did 15 min RealBench stress test, passed it and the Vcore was 1.248 V stable.

Today I turn on the computer, do some easy stuff like browsing the internet, reading forums. Just out of curiosity I take a look at HWiNFO (with is autostarting at Windows startup and has a polling rate set to 250 ms) and I see Vcore current 0.112 V, min 0 V, max 4.064 V!

I've reported this issue on the Asus ROG forum as well. According to them this is not possible since my CPU would have been fried instantly. They suspect inaccurate sensor readings.

Motherboard: ASUS Prime Z270-K
BIOS: 0610 (2017/03/25)
HWiNFO version: v5.50-3130
OS: Windows 10 Pro x64 with latest updates

SpeedFan was also running but it had every voltage sensor disabled. Only fan and temperature sensors were enabled.

 

[Martin]

This is certainly an erratic readout from the sensor.
It might be caused either by using SpeedFan, which even if not accessing the voltage rails still communicates with the Nuvoton sensor and when it's not well synchronized with HWiNFO can cause such erratic values. Another possibility would be a problem with the Nuvoton sensor, which would rarely sample invalid values.

 

[dirtyred]

I did a fresh system installation. Now the only monitoring software is HWiNFO. Will go back to using adaptive + offset voltage and will keep an eye on the readings. I'm a bit forced into using SpeedFan since my GPU temps cannot be linked to my case fans but will not install it for a few days.

 

[NLKK]

I used to have the same issue with Z370 TUF gaming plus, even on newest BIOS 0615.
however, after disabling Corsair AIO fan/pump monitoring in HWiNFO, the issue is solved.

Edit: I saw your post in ASUS ROG forum but somehow my newly created account was banned without any notice, so I couldn't reply.
Too lazy to deal with their lame auto-ban mechanism.

Edit2: Actually it's not related to Corsair LINK, but its because of Windows Power Plan. When set to "High Performance" plan then the issue is gone, but in "Balanced" plan then the issue comes back