HP 647883-B21 COMP 16GB DDR3-1333MHZ ECC CL9 DR RDIMMAddOn 16GB DDR3 SDRAM Memory Module 16 GB (1 x 16GB) DDR3 1333 PC3 10664 DDR3 SDRAM 1333 MHz Dual rank Memory CL9 1. 35 V ECC Registered 240 pin DIMM Lifetime Warranty VPN: 647883 B21 AM SKU: RSC344421 UPC: 821455232224 16 GB of memory to maintain symmetry with processor and hard drive and bring out the ultimate computing experience Up to 1333 MHz memory speed with Registered signal and CL9 to manage your routine softwares with pace and accuracy 240