HP 604504-B21 COMP 4GB DDR3-1333MHZ ECC 1.35V SR RDIMMAddOn 4GB DDR3 SDRAM Memory Module 4 GB (1 x 4GB) DDR3 1333 PC3 10664 DDR3 SDRAM 1333 MHz Single rank Memory CL9 1. 35 V ECC Registered 240 pin DIMM Lifetime Warranty VPN: 604504 B21 AM SKU: RSC136960 UPC: 821455233122 DIMM 4 GB memory allows you to have more programs open at a time DIMM 4 GB of memory makes a perfect symmetry with your latest model processor and boosts up your computer's performance Up to 1333 MHz memory speed to manage your routine