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.
All scenarios tested with two cpus and two ram kits. Only the 4 sticks at xmp doesn’t work with 14900k.