Operating System : Windows 7 Home & Pro. MAR, Windows 10 Home & Pro MAR Chipset : Q45 Express Chipset w/ICH10DO Processors : Intel Cor 2 Duo E7400, Intel Dual Core E5300, Intel Celeron 440 Memory Support : Four (4) DIMM slots , Up to 8 GB DDR3 1066MHz Hard Drive : SATA 3.0Gb/s Hard Drive 7200 rpm Removable Media : DVD-ROM/ DVD-ReWritable Expansion Bays : External: One (1) 3.5-inch, Internal: Two (2) 3.5-inch Expansion Slots : One (1) PCIe x16 Low Profile, One (1) PCIe Low Profile, Two(2) PCI Low Profile Graphics : Integrated Intel Graphics Audio : Internal Dell Business audio speaker Communications : Gigabit Ethernet I/O Ports : Front: Two (2) USB 2.0 Rear: Four (4) USB, DVI,VGA, External 24V Powered USB port,Two (2) RJ-45, DP, Two (2) Serial, Audio I/O, Two (2) PS/2 Input Devices : Standard Keyboard, Mouse (USB or PS/2) Power : 300W Dimensions : 39.65 x 34.91 x 10.93cm Weight : 9.38 kg