HP FX621AA COMP 4GB DDR3-1333MHZ ECC 1.5V DR RDIMMAddOn 4GB DDR3 SDRAM Memory Module For Server 4 GB (1 x 4GB) DDR3 1333 PC3 10664 DDR3 SDRAM 1333 MHz Dual rank Memory CL9 1. 50 V ECC Registered 240 pin DIMM Lifetime Warranty VPN: FX621AA AM SKU: RSC786631 UPC: 821455544990 DIMM 4 GB of memory to heighten your computer's performance 1333 MHz speed with Registered signal and CL9 latency to execute routine softwares at a steady pace DDR3 1333 PC3 10664 operates at an effective bus speed with minimal