I have 4x16gb kit - G.SKILL Trident Z Neo 64GB (4x16GB) RGB DDR4 3600 (PC4 28800) F4-3600C16Q-64GTZNC.

Just testing an upgrade from 12900k and got BSOD immediately.

Memtest fails with 4 sticks running at XMP, but does not fail running only one or two sticks.

Memtest does not fail on 4 sticks at XMP on the 12900k

So far memtest is running without any errors (yet) on the 14900k downclocked to 3200 mhz with all other settings at xmp levels.