Mysterious WHEA Errors

[pwate]

Though my system is "running fine" in every practical sense (don't remember the last time it crashed) I recently noticed WHEA errors flooding the event log.

I get a couple of different types, mostly:

A corrected hardware error has occurred.
Reported by component: Processor Core
Error Source: Corrected Machine Check
Error Type: Cache Hierarchy Error
Processor APIC ID: 6

And less frequently:

A corrected hardware error has occurred.
Component: Memory
Error Source: Corrected Machine Check
The details view of this entry contains further information.

My system is:

• Gigabyte GA-Z170XP-SLI Intel Z170 (Socket 1151) DDR4 ATX
• Intel Core i5-6600K 3.9GHz (Skylake)
• Corsair Vengeance LPX 32GB (4x8GB) DDR4 PC4-24000C15 3000MHz Dual Channel Kit - Black (CMK16GX4M2B30
• Super Flower Leadex Platinum 750W Fully Modular "80 Plus Platinum" Power Supply - Black
• Raijintek Aidos Direct Contact CPU Cooler - Black
• Inno3D GeForce GTX 1080Ti iChill X3 Ultra 11264MB GDDR5X PCI-Express Graphics Card (C108T3-1SDN-Q6MN

Its running on stock settings just now (I lost my BIOS profile when I flashed the BIOS after spotting the WHEA errors - oops) though it has been conservatively overclocked in the past. I don't have a note of the values but from memory the voltages, speeds & temperatures were pretty normal for this hardware.

At stock settings HWMonitor shows the vcore at around 1.06->1.12 and the frequency at 3.6. The vcore there seems a bit low (HWMonitor and my BIOS usually disagree by something like 0.02v) so I have tried bumping that up but holding the frequency constant but it hasn't had any affect on the WHEA errors.

Aside from the errors the system seems stable (doesn't crash during gaming, rendering etc. and hasn't given me problems really - its been a solid machine!) and I'm probably going to build a new PC towards the end of the year so I'd like to just ignore the errors but they are bugging me so I'm wondering if anyone has any suggestions?

 

[pwate]

I was getting Cache Hierarchy Errors, it turned out to be related to the USB 3.2 port on my X370 board. I have never used that port before but moved my PC and connected a mouse or keyboard to it and started getting the error, after I changed the port to a USB 3 port I never got the error again so think that's what caused it? USB ports can cause strange issues, had to mess about changing ports on my Intel and AMD PC's, they both have ASUS boards so thought it might be an ASUS thing?

Sadly even with no USB devices connected I am still getting these errors. The system continue to be stable enough though and is due to become a hand-me-down in the next few months so I've given up and am just going to live with it. Mysterious though!