When you undervolt check performance benchmark comparisons with stock voltage and undervolting, there might be a loss with the CPU. With nvidia GPUs there should be a loss in performance with undervolting.
i5 8600K OC 5.0GHz
Motherboard Gigabyte Z370-HD3
G.SKILL Ripjaws v 16GB F4-3200C14D-16GVK XMP Speed 3200 14-14-14-34
EVGA GeForce RTX 2070 XC ULTRA GAMING
ASUS VG279Q 27" 1920x1080p 144Hz IPS panel Gsync compatible