The FlashCut CNC architecture uses Windows for what it does well, i.e. a great user interface and graphic display of the tool path, but passes all of the real time information through a buffer to the signal generator. The signal generator has its own dedicated microprocessors that do nothing but orchestrate motor movement for multiple axes and control the I/O signals to and from multiple devices on the microsecond level.
By design, Windows is a multitasking operating system that constantly services multiple programs and peripherals in time slices on the millisecond level. Real time motion controllers like FlashCut CNC, however, require a dedicated clock that is accurate on the microsecond level. Windows is therefore not capable of outputting the timing necessary for real-time motion control by itself.