Switching speed in perpendicular recording media has been studied from micromagnetic simulations, by applying a uniform reversal field to an array of magnetic grains. Increasing the damping constant reduces the switching time, but a weak exchange interaction leads to an increase in the switching time. A linear relationship is found between the switching time and the head field rise time for different field strengths, damping constants and weak exchanges. A 20 degrees field angle to the perpendicular direction substantially improves the switching speed.