Operating System : Windows 10 Home & Pro MAR, Ubuntu Linux, Free DOS Chipset : Intel H81 Express chipset Processors : Intel Core i3, i5, i7 4th Gen Memory Support : Two (2) DIMM slots , Up to 16 GB DDR3 SDRAM  Hard Drive : 160MB to 2TB , 64GB to 1TB Solid State Drive (optional) Removable Media : HP Blu-ray BDXL Writer Drive, HP SuperMulti DVD Writer Drive, HP DVD-ROM Drive Expansion Bays : External: One (1) 3.5-inch Internal: One (1) 3.5-inch, One (1) 2.5-inch Expansion Slots : One (1) PCI Express x16s (LP), Three (3) PCI Express x1 (LP) Graphics : Intel HD Graphics on all models (integrated on processor) Audio : Realtek ALC221 codec Communications : Realtek RTL8151GH-CG GbE I/O Ports : Front: Two (2) USB 3.0, Two (2) USB 2.0, Headphone/Mic, Rear: Four (4) USB 2.0, VGA, DVI-D Input Devices : HP Standard Keyboard, HP 2-Button Optical Scroll Mouse Power : 240W active PFC Dimensions : 38.05 x 33.7 x 10 cm Weight : 5.9 kg