SAMSUNG Samsung DDR3-1600 4GB512Mx64 CL11 Memory / M378B5173QH0-CK0 / Module Size: 4GB Package: 240-pin DIMM Feature: DDR3 PC3-12800 Specs: DDR3 PC3-12800 , CL=11 , Unbuffered , NON-ECC , DDR3-1600 , 1.5V , 512Meg x 65 Lifetime warranty. Compatible to desktop PC's only. Please, make sure, your desktop supports 4GB ram per slot.