16GB (4 X 4GB) DDR3 1600MHz PC3-12800 240-pin Memory RAM DIMM Kit for Desktop PC by NEMIX RAM at Amazon.com
CMS 16GB (4X4GB) DDR3 10600 1333MHZ ECC Non Registered DIMM Memory Ram Upgrade Compatible with HP/Compaq® Workstation Z820 1333Mhz Ecc Unbuff for Server Only - B126 at Amazon.com