Question

Why do some plates move faster than others

Answer 1

The subducting plate which controls the velocity of the plate's movement,and the rate at which a plate sinks depends mostly on its age,temperature,density: older plates are cooler/denser, they sink at a higher velocity than younger plates.

Answer 2

A new study suggests these tectonic plates control their own speed more than the mantle does. ... The velocities of these plates and the velocities of the boundaries between these plates vary significantly on Earth.