OFFTEK 4GB Replacement Memory RAM Upgrade for HP-Compaq Workstation Z600 (DDR3-10600 - ECC) Server Memory/Workstation Memory at Amazon.com
CMS 12GB (3X4GB) DDR3 10600 1333MHZ ECC Registered DIMM Memory Ram Upgrade Compatible with HP/Compaq® Workstation Z600 C2 Seires Only Ddr3 Ecc Reg for Server Only - C20 at Amazon.com
4GB 240Pin DDR3-1333 PC3-10600 ECC Unbuffered RAM Upgrade for HP Z600 Rev B3 | eBay