Do you mean PWM base frequency? The effective number of speed steps is the kernel clock frequency (eg 25 kHz) divided by the base frequency. So if you have the kf set to 25 kHz and the base frequency to 500 Hz there will be in effect 50 discrete speed steps. If the bf was set to 25 Hz which is a common number then there will be 1000 steps, so effectively smoother control. Whether it makes a significant difference is doubtful.
Sent from my iPad using Tapatalk