Ywell said @DoomedFPV… no point getting an F1 board (unless it is free) since the latest firmware cannot run on them anymore. Current sweet spot is f4 boards.
Developers are working at optimising the code for f7 chips so should see more of these FC in 2018… but I am also at the opinion of thinking from a human point of view can we really notice the difference between 8khz and 32khz?
I have not really looked into it but even at 8khz you are telling the motor to change speed several times before it even completes a single rotation. And from a physics point of view does I wonder if the motor actually has time to slow down/speed up fully before getting the next speed update?
Excuse my ramblings, am just writing my thoughts… but I do agree with what doomedfpv said. I think the main benefit of faster CPU are better sensor fusion algorithms and other extra features apart form ever increasing flight loop times.