Thermaltake TOUGHRAM RGB White DDR4 4000MHz 16GB (8GB x 2) 16.8 Million Color RGB Alexa/Razer Chroma/5V Motherboard Syncable RGB Memory R022D408GX2-4000C19A at Amazon.com
G.Skill Trident Z NEO Series 32GB (2 x 16GB) 288-Pin SDRAM DDR4 4000 (PC4-32000) CL18-22-22-42 1.40V Dual Channel Desktop Memory Model F4-4000C18D-32GTZN at Amazon.com
XLR8 Gaming EPIC-X RGB™ 4000MHz Desktop Memory
Patriot Viper Elite II DDR4 8GB(1 x 8GB) 4000MHz Single Memory Module at Amazon.com