If you want to adjust how many steps of particle simulation take place per animation frame, you can use the steps per frame control in the ParticleSettings properties panel. Sometimes simulations cannot generate enough accuracy only calculating once per frame, and the resulting particle movement can appear jagged. Steps per frame forces the simulation to assess the movement of the particles multiple times per frame to enable a more analogue movement. You should enter the lowest value you can, as having an unnecessarily high value can slow down your particle calculations.