Whether or not to enable zero-crossing detection on state transitions can be a trade-off between accuracy and performance. Generally when detecting zero crossings, a Simulink® model accurately simulates mode changes without unduly reducing step size. However, for systems that exhibit chattering — frequent fluctuations between two modes of continuous operation — enabling zero-crossing detection may impact simulation time. Chattering requires a Simulink model to check for zero crossings in rapid succession, resulting in excessively small step sizes which can slow simulation. In these situations, you can disable zero-crossing detection, choose a different zero-crossing detection algorithm for your chart, or modify parameters that control the frequency of zero crossings in your Simulink model. See Preventing Excessive Zero Crossings in the Simulink User's Guide.