HP 713977-B21 COMP 4GB DDR3-1333MHZ ECC CL9 DRX8 UDIMMAddOn 4GB DDR3 SDRAM Memory Module 4 GB (1 x 4GB) DDR3 1333 PC3 10664 DDR3 SDRAM 1333 MHz Dual rank Memory CL9 1. 35 V ECC Unbuffered 240 pin DIMM Lifetime Warranty VPN: 647907 B21 AM SKU: RSC534243 UPC: 821455230060 4 GB of memory to heighten your computer's performance Up to 1333 MHz memory speed to manage your routine softwares with pace and accuracy 240 pin pin DDR3 SDRAM interface synchronizes electrical and clock signals for an efficient data