According to one prominent member of the overclocking community, the VRM cooling on X299 motherboards isn't good enough to keep the boards stable -- and no overclocker should buy a board with just one ...
Calling up the hivemind here, My Asus Prime X299 started dying recently after 2 years of service, (frequent reboots, even in the UEFI, even at stock speeds, tried different RAM, GFX Cards, Bios ...