In video-games, an unintentional or unexpected delay between the start and end of a process, usually to a detrimental effect on gameplay. Lag can occur in any of the many different processes in a video-game, to vastly differing effects depending on the source: Frame lag: A direct delay in the rate at which a frame is processed. This is usually the result of having too many objects active at once – the physics, rendering and other processes of which must each be calculated on every frame. In turn, this results in choppy movement, and depending on how the code is handled, either slowed gameplay compared to real-time (when the lag is not accounted for) or a loss of player control precision (when it is accounted for). In multiplayer games, this is often called client-side lag, as opposed to server-side lag. Rendering lag: A delay in the rate at which an otherwise-processed frame is rendered, usually due to a very large number of polygons or visual effects on screen at once. This can have similar visual effects as frame lag, but can alternatively result in frames being rendered incompletely – missing visual details, textures, particle effects or occasionally entire objects. Occasionally, a similar effect can be seen with layered audio cues. Server-side lag: A delay appearing only in online multiplayer games, between the client (the player’s device) or the server sending information across the internet, and the counterpart receiving said information. This rarely looks like frame lag or rendering lag, and can instead cause a variety of effects such as dropped player inputs, desynchronisation between the player and server’s versions of events, rubber-banding (where entities appear to ‘snap’ between different positions), or in worst-case scenarios, the player being removed from the server entirely, or kicked.
