Dell Optiplex 740, Dual Core @ 2.5 GHz, 4.0 GB RAM, 160GB HD, Windows 7 Pro 64 BIT Pre-installed Windows 7 64Bit Pro Edition Operating System Business Class-AMD Athlon X2 Dual-Core Processors 2.3Ghz 2GB DDR2 memory installed (1 Stick, 3 available slot), upgradable up to 8GB of RAM 80GB SATA Hard Drive Multi Writer DVDR/RW and CD/RW