Why Microstepping Trades Torque for Smoothness
A stepper motor's native resolution is fixed by its physical design — commonly 200 full steps per revolution (1.8 degrees per step) — but microstepping electronically subdivides each full step into smaller increments by driving the coil currents at intermediate proportions rather than fully on/off, producing much smoother motion and finer positional resolution than the motor's native step count would suggest.
This smoothness comes with a real tradeoff: microstepping doesn't add genuine mechanical resolution or increase the motor's actual holding torque at each microstep — the torque curve across microsteps is generally less consistent than at full steps, meaning very fine microstepping can reduce effective torque and positioning accuracy under load, even though the commanded position resolution has increased. This is exactly why microstepping settings are chosen as a balance (smoothness and quietness versus torque consistency), not simply maximized for the highest possible subdivision.
The actual output RPM depends on step pulse frequency, the motor's steps-per-revolution (already multiplied by the microstepping factor), and any gearbox reduction stage — all three combine multiplicatively, which is why a small change in any one of them (especially the microstepping factor) has an outsized effect on final commanded speed if not accounted for correctly.