CMS 16GB (4X4GB) DDR3 12800 1600MHz ECC Registered DIMM Memory Ram Upgrade Compatible with HP/Compaq® Workstation Z620 Ddr3 Ecc Reg for Server Only at Amazon.com
HP 16GB PC3-12800 DDR3-1600 2Rx4 1.5v ECC Registered RDIMM (HP PN# 672612-081) at Amazon.com