What is G-Sync
G-Sync is a proprietary adaptive sync technology made by Nvidia. It aims to give gamers a smoother gameplay experience by matching a monitor’s refresh rate with the frame rate that the GPU is pushing out, thus eliminating screen stuttering or tearing. It is currently available on all (low-)mid to high tier GTX graphics cards (GTX 650Ti and newer), though gaming monitors don’t come standard with this technology, as the cost of implementing G-Sync in a monitor raises the price. If you wish to use G-Sync, make sure to double check if your monitor is compatible.
G-Sync is not to be confused with V-Sync, which is an option in many games and is not a technology developed by Nvidia.
Regular (i.e. ‘non G-Sync compatible) monitors refresh the image on the screen at a fixed rate (i.e. their ‘refresh rate’). If you’ve got a 100Hz monitor it’ll be refreshing the screen 100 times per second. The framerate that your GPU puts out can vary though, depending on many factors (such as how much action is on screen, the power of said graphics card, …) and that isn’t ideal to get a smooth looking game.
If your PC (and thus, more importantly; your GPU) isn’t powerful enough to render enough frames to match your monitor’s refresh rate it will cause the image on your screen to stutter. This isn’t a massive issue in and of itself, but it’s not the most pleasant thing to look at and can hamper performance in, for example, multiplayer games. If your system is rendering more frames than what your monitor can display it can cause screen tearing (see the image above). This, again, isn’t a major issue in and of itself (some people don’t really mind stuttering or tearing, as long as it isn’t overdone) but it’s not nice to look at and can cause ingame performance issues.
How G-Sync Comes In
G-Sync, when used correctly, eliminates screen tearing and screen stuttering by changing the monitor’s refresh rate (this is why you need a G-Sync compatible monitor and not just any monitor) to match the amount of frames the GPU is pushing at all times. This ensures that the GPU is never pushing out less frames than what the display is rendering, nor will it push out more frames than what the display is capable of. Note that G-Sync will cease to work properly if the framerate drops below 30 FPS.
G-Sync does what it promises to do expertly, however it is a proprietary technology, meaning that you have to invest in a monitor with a G-Sync module (which will cost extra) and you will need an Nvidia graphics card. It is possible to use G-Sync monitors with AMD cards, but the framerate will not be synchronised, thus giving on one the major advantages of getting a G-Sync compatible monitor.
If you are willing to invest in a G-Sync monitor and you want to play your games without suffering from any screen tearing or stuttering then G-Sync can be the answer to your problems, provided you’re willing to pay a bit more.