I'm not sure if this has to do with XMP settings, but when load testing my new build, I've been experiencing voltages that meet or exceed 1.42V (sometimes hitting 1.449V) on all cores.
My current specs are:
CPU: Intel I7-8700 Non-K
Mobo: ASRock Z370 Killer SLI/AC
Cooler: Cyrorig H7
RAM...