Operating System : Windows 10 Pro for Workstations, Windows 10 Pro for Workstations Downgrade to Windows 7, Red Hat Linux, Suse Linux Chipset : C621 Processors :One or two Intel Xeon Scalable Processor family CPUs Memory Support : Six channel memory up to 1.5TB DDR4 Hard Drive : SATA or SSD or M2 SSD Removable Media : DVD ROM (optional) Expansion Bays : N/A Expansion Slots :: All slots PCIe Gen 3: (2) PCIe x16, (2) additional x16 slots with 2nd CPU; (1) PCIe x8 open ended, (1) x16 wired as x 4 Graphics : depending on model Audio :Realtek ALC3234 Communications :: Intel i219 & i210 Gigabit Ethernet I/O Ports Front 2 x USB 3.1 Gen 1 Type A, 2 x USB 3.1 Type C,1 x Universal Audio Jack Internal 1 x USB 2.0 Type A, Rear 6 x USB 3.1 Gen 1 Type A, 1 x Serial, 2 x RJ45 Network, 2 x PS2, 1 xAudio Line out, 1x Audio Line in/Microphone Power : 1400W Dimensions : 433mm x 218mm x 566mm Weight : aprox. 20.4kg