Dell memory - 4 GB - DIMM 240-pin - DDR3 Dell Snpp382hc/4g 4 Gb Certified Replacement Memory Module For Optiplex And Vostro Desktops - 1333mhz Ddr3-1333/pc3-10600 - Non-ecc - Unbuffered - Cl9 - 240-pin Dimm