Crucial Technology 4GB 288-Pin RDIMM DDR4 (PC4-21300) Memory Module, CL=19, Registered, 2666 MT/S Speed, ECC, 1.2V, 512Meg x 72, Single Ranked, x8 Based at Amazon.com
G.Skill Trident Z RGB Series 16GB (2 x 8GB) 288-Pin SDRAM (PC4-25600) DDR4 3200 CL16-18-18-38 1.35V Dual Channel Desktop Memory Model F4-3200C16D-16GTZR at Amazon.com
You can already buy TeamGroup's DDR5 memory kits on Amazon and Newegg | TechSpot