G.SKILL Trident Z Royal Series 32GB (2 x 16GB) 288-Pin DDR4 SDRAM DDR4 4000 (PC4 32000) Intel XMP 2.0 Desktop Memory Model F4-4000C18D-32GTRS - Newegg.com
Crucial 16GB DDR4 SDRAM Memory Module at Amazon.com
Differences Between DDR2, DDR3 and DDR4 Memory | Crucial.com