HP 500658-B21 COMP 4GB DDR3-1333MHZ ECC 1.5V DR RDIMMAddOn FACTORY ORIGINAL 4GB DDR3 1333MHz Dual Rank LP Module 4GB 1333MHz ECC DDR3 SDRAM DIMM VPN: 500658 B21 AM SKU: RSC385227 UPC: 821455157213 DIMM 4 GB of memory makes a perfect symmetry with your latest model processor and boosts up your computer's performance 1333 MHz speed to execute routine softwares at a steady pace Up to 1333 MHz memory speed with Registered signal and CL9 to manage your routine softwares with pace and accuracy