The RuneScape clock is a term that is used to refer to the time-frame used for actions in RuneScape. RuneScape runs on units of time of approximately 0.6 seconds which are sometimes called "ticks." All actions are a multiple of this basic tick time. This includes any instant where a message appears in the chat interface, any instant that experience is gained, any instant that a monster spawns, and any other actions a player performs, including animations (hence players being able to perform animations in sync with eachother rather easily). Purely client sided occurences are independent of the game tick (i.e. loading new regions).