FPS

Frame rates in video games refer to the speed at which the image is refreshed (typically in frames per second, or FPS). Many underlying processes, such as collision detection and network processing, run at different or inconsistent frequencies or in different physical components of a computer. FPS affects the gaming experience in two ways: low FPS does not effectively give the illusion of motion and affects the user's capacity to interact with the game, while FPS that varies substantially from one second to the next depending on computational load produces uneven, "choppy" movement or animation.

The first 3D first-person game for a personal computer, 3D Monster Maze, had a frame rate of approximately 6 FPS, and was still a success. In modern action-oriented games where players must visually track animated objects and react quickly, frame rates of between 30 and 60 FPS are considered acceptable by most, though this can vary significantly from game to game. Modern action games, including popular console games such as Halo 3, are locked at 30 FPS maximum, while others, such as Unreal Tournament 3, can run well in excess of 100 FPS on sufficient hardware. Additionally some games such as Quake 3 Arena perform physics, AI, networking, and other calculations in sync with the rendered frame rate - this can result in inconsistencies with movement and network prediction code if players are unable to maintain the designed maximum frame rate of 125 FPS. The frame rate within games varies considerably depending upon the complexity of the individual frame to render, or with the hardware configuration (especially in PC games). When the computation of a frame consumes more time than intended, the frame rate decreases. This instability causes stuttering and screen tearing.

Frame rate in video games is a delicate trade off between picture fidelity and render time (which translates into FPS). Unlike movies, video games depend on the interaction between consumer and game. Lower frame rates affect this feedback loop with choppy motion and additional input delay. However a trend to low frame rate high fidelity titles was perceivable in the last years. This is mostly because of the mismatch between console platforms steady stated computational power and the demand of higher fidelity graphics. For many game studios the shift to 30FPS is a notable gain considering that lower frame rates are less apparent for the untrained eye than reduced picture quality.

A culture of competition has arisen among game enthusiasts with regard to frame rates, with players striving to obtain the highest FPS possible, due to their utility in demonstrating a system's power and efficiency. Indeed, many benchmarks (such as 3DMark) released by the marketing departments of hardware manufacturers and published in hardware reviews focus on the FPS measurement. LCD monitors of today are built with three major refresh rate in mind. The most common is 60 Hz, which can be used at any resolution without requiring high quality computer systems to render, and then 120 Hz and 144 Hz. The 120 Hz standard also supports what is known as 'lightboost' technology in some monitors, where strobing lights behind the monitor reduce ghosting at high FPS.

Beyond measurement and bragging rights, such exercises do have practical bearing in some cases. A certain amount of discarded “headroom” frames are beneficial for the elimination of uneven (“choppy” or “jumpy”) output, and to prevent FPS from plummeting during the intense sequences when players need smooth feedback most.

Without realistic motion blurring, video games and computer animations do not look as fluid as film. When a fast moving object is present on two consecutive frames, a gap between the images on the two frames contributes to a noticeable separation of the object and its afterimage in the eye. Motion blurring mitigates this effect, since it tends to reduce the image gap when the two frames are strung together. The effect of motion blurring is essentially superimposing multiple images of the fast-moving object on a single frame. Motion blurring makes the motion more fluid for some people, even as the image of the object becomes blurry on each individual frame. Motion blur can also induce headaches when people play a game that requires concentration.

A high frame rate still does not guarantee fluid movements, especially on hardware with more than one GPU. This effect is known as micro stuttering.