256GB on sTR4, Z2EA board (or Aorus Xtreme)

[orcinus]

What is the fastest, currently available memory kit of 32GB modules that can be used on Z2EA or Aorus Xtreme and 3970X/3990X in 8 slots to achieve 256GB.
XMP is handy, but faster RAM downclocked from XMP will also work, manually set up I guess.