So X299 Dark, Bios 1.29. If I enable XMP then the CPU will not boost to it's proper frequencies if I leave the CPU settings at auto.
If I disable XMP with the CPU at Auto the CPU will boost just as it should.
With XMP disabled and the CPU settings in the bios set to auto the cores will boost to 4.6-4.8 depending on the workload.
If I enable XMP and leave the CPU settings at auto the CPU will not boost past 3.8ghz on any core regardless of workload.