HP 669322-B21 COMP 4GB DDR3-1600MHZ ECC DRX8 UDIMMAddOn 4GB DDR3 SDRAM Memory Module 4 GB (1 x 4GB) DDR3 1600 PC3 12800 DDR3 SDRAM 1600 MHz Dual rank Memory CL11 1. 50 V ECC Unbuffered 240 pin DIMM Lifetime Warranty VPN: 669322 B21 AM SKU: RSC317845 UPC: 821455230053 4 GB of memory to heighten your computer's performance 1600 MHz memory speed for great multitasking capability 1600 MHz of memory speed allows you to browse web, listen to songs and use routine software simultaneously