4GB DDR3 Memory Upgrade for HP Compaq ProLiant Workstation Z1 PC3-12800E ECC Unbuffered DIMM 240 pin 1600MHz RAM (PARTS-QUICK BRAND) 4GB DDR3 PC3-12800E 1600MHz ECC Unbuffered DIMM for HP Compaq ProLiant Workstation Z1 Capacity: 4GB Speed: PC3-12800E DDR3 1600MHz Form Factor: 240 pin DIMM Halogen Free; ROHS Warranty: Lifetime