Ran into this with my 2700x on my Strix X470 - it was godawful picky on running 32gb 3200 c14 kits with 4x8gb. I went through 3 of 4 kits before I wound up replacing it with a Crosshair VII and it worked like a charm with my Vengeance Pro kit. The Strix would fail memtest left and right with Windows being sketchy under load. RMA'd it back to Asus.