IBM 49Y1407 COMP 4GB DDR3-1333MHZ ECC CL9 DRX8 RDIMMAddOn 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 Registered 240 pin DIMM Lifetime Warranty VPN: 49Y1407 AM SKU: RSC655962 UPC: 821455232958 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 Registered signal and CL9 latency for remarkable multitasking capability 240 pin pin