Asus Zenith Extreme RAM issues

Hi, would anyone have any knowledge about BIOS settings on a Rog Zenith Extreme with Threadripper1950 to get RAM working with 8 slots occupied?

F4-3200C16D-16GFX
G.Skill Flare X 8GB 3200MHz DDR4 Desktop Memory Kit
4 sticks of Ram currently works in
D1, C1, A2, B2

Any more and no boot.

Much appreciate any help