Operating Systems come in 3 general types: Windows, Macintosh and Linux. These then have seperate models, aside from Linux where you have to self program the functions. the models are then divided into x32 and x64, depending on the cpu you are using, i7's though are locked to x64, as without the DirectX11 features it would be the same clock speed as a x32 i5. Intel Xeon's though are locked to x32, as it was only meant to run light OS tasks, the heavy hauling is programed through a third-party control unit. The OS also handles runtime events, where as Control Tasks are handled by the motherboards onboard processer.