I am using two 64GB PC4-2666 LRDIMM memory (128GB 2x 64GB PC4-2666 LRDIMM GIGABYTE G250-G51 MG50-G20 H231-G20 Memory RAM | eBay). I have one stick in slot DIMM_P0_C0 and one stick in slot DIMM_P1_E0 Here is the manual: https://download.gigabyte.com/FileList/Manual/server_ma...