about set clock rate and actual clock rate

Hi there,

  I am connecting the PFI pin to clock genrator which output clock signal at rate 1MHz (constant). But in the DAQmx Timing (Sample Clock).vi, I can set the sampling rate to anything other then 1MHz? So what happen if I set it to 1kHz instead? Will it use 1kHz or 1MHz actually?

What happens if I choose the rate to a numeber such that 1MHz is not dividible by that number?

The last quesiton. If I use the PFI as the source for timed sequence, will it really works at that high frequency? I doubt that becaue in windows, the time resolution interval is about 1ms, so what will happen if I use 1MHz clock to drive it?