Five USB 2.0 ports (two on front panel, three on back panel).Four FireWire 800 ports (two on front panel, two on back panel).Hyper-Threading technology for up to 8 virtual cores.Turbo Boost dynamic performance up to 3.06GHz.8MB of fully shared 元 cache per processor.One 2.8GHz Quad-Core Intel Xeon W3530 “Nehalem” processor.Hyper-Threading technology for up to 16 virtual cores.Turbo Boost dynamic performance up to 2.66GHz.12MB of fully shared 元 cache per processor.Two 2.4GHz Quad-Core Intel Xeon E5620 “Westmere” processors.