HP 501538-001 COMP 16GB DDR3-1066MHZ ECC CL9 QR RDIMMAddOn 16GB DDR3 SDRAM Memory Module 16 GB (1 x 16GB) DDR3 1066 PC3 8500 DDR3 SDRAM 1066 MHz Quad rank Memory CL9 1. 35 V ECC Registered 240 pin DIMM Lifetime Warranty VPN: 501538 001 AM SKU: RSC259115 UPC: 821455579305 DIMM 16 GB of memory to maintain symmetry with processor and hard drive and bring out the ultimate computing experience Up to 1066 MHz memory speed with CL9 latency to manage your routine softwares with pace and accuracy 240 pin pin