HP 647899-B21 COMP 8GB DDR3-1600MHZ ECC SRX4 RDIMMAddOn 8 GB DDR3 SDRAM Memory Module 8 GB (1 x 8GB) DDR3 1600 PC3 12800 DDR3 SDRAM 1600 MHz Single rank Memory CL11 1. 50 V ECC Registered 240 pin RDIMM Lifetime Warranty VPN: 647899 B21 AM SKU: RSC151017 UPC: 821455229934 RDIMM 8 GB capacity is enough to execute all memory hungry programs simultaneously RDIMM 8 GB bar will run multiple applications together and enhance your computer's performance 1600 MHz memory speed for great multitasking capability