HP 647657-071 COMP 4GB DDR3-1333MHZ ECC CL9 DRX8 UDIMMAddOn 4GB DDR3 SDRAM Memory Module 4 GB (1 x 4GB) DDR3 1333 PC3 10666 DDR3 SDRAM 1333 MHz Dual rank Memory CL9 1. 35 V ECC Unbuffered 240 pin DIMM Lifetime Warranty VPN: 647657 071 AM SKU: RSC124475 UPC: 195285045720 DIMM 4 GB of memory makes a perfect symmetry with your latest model processor and boosts up your computer's performance Up to 1333 MHz memory speed with Unbuffered signal for remarkable multitasking capability 240 pin pin DDR3 1333 PC3