Operating System :Windows 7 Home & Pro. MAR, Windows 10 Home & Pro MAR, Ubuntu Linux, Free DOS Chipset :Intel C216 Chipset Processors :Intel® Xeon? Processor E3-1200v2 Family; 3rd generation Intel® Core™ i7 and i5; 2nd generation Intel Core i3 Memory Support :Up to 32GB 1600MHz ECC or 16GB non-ECC DDR3 memory; 4 DIMM slots Hard Drive :Up to two 3.5" SATA drives: 250GB, 500GB, 1TB, 2TB; Or up to four 2.5" SATA drives: 320GB, 500GB Removable Media :Up to two optional optical drives: DVD-ROM; DVD+/-RW; BD-RE Expansion Bays :Two internal 3.5" hard drive bays; two external 5.25" optical bays Expansion Slots :One PCIe x16 Gen 3; one PCIe x16 Gen 2 wired x4; one PCIe x1; One PCI 32bit/33MHz Graphics :Support for one PCI Express? x16 Gen 3 graphic card up to 75W (total for graphics) Audio :Integrated Realtek ALC269VB High Definition Audio Communications :Integrated Intel 82579 Gigabit Ethernet controller I/O Ports :Front: Two USB 2.0, Two USB 3.0, Mic/Headphones; Rear: Four USB 2.0, Two USB 3.0, VGA, DP, Serial. Two PS2, Audio I/O Input Devices :Dell Entry keyboard Dell USB Optical Mouse Power :320W 90% efficient (80 Plus? Gold Certified); 275W 65% efficient Dimensions :(HxWxD) 14.17" x 6.89" x 17.13"; 360mm x 175mm x 435mm Weight :N/A