What’s the use of sync technologies? They are used to prevent screen tearing.
Essentially, screen tearing can happen whenever the in-game FPS is higher than your monitor’s refresh rate. Most mainstream gaming monitors refresh at 60 Hz, meaning that they can only display 60 frames per second. Anything higher and screen tearing will begin to manifest.
Of course, there are monitors with higher refresh rates of 120 Hz, 144 Hz, and even 240 Hz, but not even they are immune to screen tearing – whenever the FPS overtakes the refresh rate, tearing is bound to happen.
V-Sync
The way V-Sync works is rather simple. All it does is impose a framerate cap, limiting the maximum FPS to the equivalent of the monitor’s refresh rate. Obviously, this will prevent screen tearing (see the above picture) from occurring because your GPU won’t be rendering more frames than what the monitor can display.
The first and most obvious issue is that frame rates will be limited to the refresh rate of your display, so while tearing may be significantly reduced you won’t reach the performance ceiling of your GPU. Vsync can also introduce input lag which, while generally fairly minor, can become problematic for genres that demand high levels of precision like rhythm or fighting games. It can also cause issues when displaying videos or movies filmed at significantly slower frame rates, creating a juddering effect where people and objects shake or move strangely on screen. FreeSync attempts to address some of these limitations.
FreeSync
FreeSync dynamically adapts the display refresh rate to variable frame rates, which result from irregular GPU load when rendering complex gaming content, as well as the lower fps used by fixed video content. This helps remove stuttering delays caused by the video interface having to finish the current frame, and screen tearing when starting a new frame in the middle of transmission (with vertical sync off). The range of refresh rates supported by the standard is 9–240 Hz, although monitors might have narrower limits. FreeSync can be enabled automatically by plug and play, making it transparent to the operating system and end user.
Transitions between different refresh rates are seamless and undetectable to the user. The sync mechanism keeps the video interface at the established pixel clock rate but dynamically adjusts the vertical blanking interval. The monitor keeps displaying the currently received image until a new frame is presented to the video card’s frame buffer, then transmission of the new image starts immediately. This simple mechanism provides low monitor latency and a smooth, virtually stutter-free viewing experience, with reduced implementation complexity for the timing controller (TCON) and display panel interface. It also helps improve battery life by reducing the refresh rate of the panel when not receiving new images.
G-Sync
Nvidia was first on to the market with its G-Sync technology, with launch partners including AOC, Asus and Acer. The technology is impressive but it has a slight drawback. In order to be G-Sync compatible, the screens need G-Sync specific hardware that’s rather expensive, unofficially adding around Rs8000-25000 on the price, depending on the spec of the monitor.
One clear difference between Nvidia G-Sync and AMD FreeSync is how they handle graphics cards that produce higher frame rates than a monitor can handle. G-Sync locks frame rates to the upper limit of the monitor while FreeSync (with in-game Vsync turned off) will allow the graphics card to produce a higher frame rate. This introduces tearing, but also means that input lag is at an absolute minimum, which is important for twitch gamers such as those who play FPS titles.
Who is the winner?
Aside from the visual experience, there’s a hidden benefit of using G-Sync/FreeSync over VSync: the reduction of input lag. This is the time it takes your monitor to respond to your input – for example, a mouse click or swipe.
When using AMD’s or Nvidia’s technologies, unwanted input lag is kept to a minimum, though, still existent, it’s nowhere near as bad as VSync. Here, the software-driven technology eliminates screen tearing but adds noticeable lag. By playing a fast-paced FPS, your monitor will feel sluggish and less responsive. It’s a night and day difference to a casual gamer, let alone for those who’re in the competitive scene.