Resource Usage of Switches (Switching)

Question

I'm looking for documentation or a brief on performance usage (CPU / RAM) of switching during game-play.   For instance, if you have a music switch that changes based on game state (Many NPCs, Some NPCs, Low Number of NPCs vs. None) and it switches often (every .5 to 1 second), what is the impact to CPU / RAM?   

I'll be performing additional performance monitoring, but was also looking for a chart or information on the effect of switching on resources if one was to be had.

Thanks!