Operating System :Windows 10 Home & Pro MAR, Ubuntu Linux, Free DOS Chipset :Intel C602 Processors :Intel Xeon E5-2600 Series, Intel Xeon E5-2600 v2 Series Memory Support :16 slots (8 slots per CPU), 3-channel DDR3, RDIMM or UDIMM, ECC, LR DIMMs,1066/1333/1600 MT/s Hard Drive :250GB to 3TB SATA 3.0-Gb/s, 300GB to 1.2TB SAS, 128GB to 1TB SSD Drives Removable Media :16X DVD-ROM SATA Drive, 16X DVD+/-RW SuperMulti SATA Drive, Blu-ray Writer Expansion Bays :External: Three (3) 5.25-inch, Internal: Four (4) 3.5-inch Expansion Slots :3 PCIe x16 Gen3 Slots (3rd on 2nd CPU), PCIe x16 (x8)(on 2nd CPU), 1 PCIe x8(x4), 1 PCIe x8(x4), 1 PCI Slot Graphics :N/A Audio :Integrated Intel/Realtek HD ALC262 Audio Communications :Integrated Intel 82579LM PCIe GbE Controller I/O Ports :Front: 1 USB 2.0, 2 USB 3.0, Headphone/Mic, Rear: 4 USB 2.0, 2 USB 3.0, 2 PS2, 1 Serial, Audio I/O Input Devices :Standard Keyboard (USB or PS/2) Mouse (USB or PS/2) Power :Choice of 850W Dimensions :44.4 x 20.3 x 52.5 cm Weight :21 kg