CMS 32GB (2X16GB) DDR3 12800 1600MHz ECC Registered DIMM Memory Ram Upgrade Compatible with HP/Compaq® Workstation Z620 DDR3 for Server Only - B17 at Amazon.com
32GB Kit (2x16GB) DDR3-1600MHz PC3-12800 ECC RDIMM 2Rx4 1.35V Registered Memory for Server and by NEMIX RAM at Amazon.com