Drive frequenzy
 

What isoperating frequency ?

On my Anaconda 1/8 brushless esc it's possible to select 8 or 16khz operating frequency but i don't know what this means ?

It's just the switching speed of the FETs. Depending on the inductance of the motor, you can get better driveability. Try both and see which one you like best while monitoring motor/ESC temps.

Usually, 8khz would be enough and probably ideal, but ya, depends on the motor really. The lower you can go without affecting driveability the better as there would be less switching and core losses.

In general:

Faster switching = higher esc temps, cooler motor temps
Slower swithching = cooler esc temps, higher motor temps