Operating System :Windows 7 Home & Pro. MAR, Windows 10 Home & Pro MAR, Ubuntu Linux, Free DOS Chipset :Intel® 5400 chipset Processors :Dual-core Intel® Xeon? 5200 series processors; Quad-core Intel® Xeon? 5400 series processors; Memory Support :Up to 64GB1 quad-channel 667MHz ECC and 800MHz ECC memory; Up to 16 DIMM slots; Hard Drive :SATA 3.0Gb/s 7200 RPM 16MB up to 1.0TB; SATA 3.0Gb/s 10K RPM 16MB up to 160GB; SAS 15K RPM up to 300GB Removable Media :CD-RW/DVD Combo, DVD-ROM, DVD+/-RW, Blu-ray, USB Floppy Drive, USB media card reader Expansion Bays :Four internal 3.5? hard disk drive bays; Three external 5.25? optical bays; One external 3.5? flex bay Expansion Slots :One PCI-e x8 slot wired as x4; Two PCI-e x16 Gen 2 slots; Three PCI-X 64bit/100MHz slots, One PCI 32bit slot; Graphics :Support for 2 PCI Express x16 Gen 2 graphics cards up to 225 watts Audio :Integrated High Definition Audio Communications :Integrated Broadcom? 5754 Gigabit Ethernet controller I/O Ports :Front: Two USB 2.0, Mic/Headphone; Rear: Five USB 2.0, Two PS2, Two Serial, Audio I/O Input Devices :Dell Enhanced QuietKey USB; Enhanced Multimedia USB; Smart Card keyboard USB Dell USB two-button mouse and Dell USB optical two-button scroll mouse Power :980 watt 80%+ Efficiency Power Factor Correcting (PFC) power supply Dimensions :(WxHxD) 8.5? x 22.26? x 22.3?, 21.59cm x 56.54cm x 56.6cm Weight :N/A