Screen tearing explained: causes, V-Sync and variable refresh rate fixes

The mismatch is measured in frames per second and hertz. A GPU produces frames per second, while a monitor refreshes a number of times per second. Basic monitors refresh 60 times per second, or 60Hz, while gaming monitors often offer 144Hz, 240Hz or higher; 1,000Hz displays are now on the market. When the GPU writes a new frame into the buffer before the monitor has finished scanning the previous one, the monitor can scan different horizontal bands from different frames. That produces the jagged split known as screen tearing, where, for example, the top of a tree appears beside its trunk. PC gaming sees the issue most often, but console players can encounter it too.

V-Sync, short for vertical synchronization, tries to prevent tearing by forcing the GPU to wait for the monitor's refresh cycle before sending the next frame. On a 60Hz display, a game would typically render around 60 frames per second; on a 144Hz display, it would render 144. This can stabilize the image and reduce GPU workload, power consumption and heat. But if the GPU cannot keep up with the monitor, the game may feel as if it is running at 30 frames per second instead of 60, depending on the setup. V-Sync can also introduce input lag because frames follow a strict delivery schedule. That delay may be unnoticeable in a slow-paced adventure game, but it can make a competitive shooter feel heavy and sluggish.

Variable refresh rate technologies take a more flexible approach. G-Sync and FreeSync let the monitor adjust its refresh rate dynamically to match the frames the GPU is producing, rather than forcing the GPU onto a fixed schedule. Traditionally, G-Sync uses a hardware module inside officially supported monitors to coordinate with the GPU, waiting to draw the next frame until the GPU completes it. Newer G-Sync Compatible monitors can use the feature without that dedicated hardware, and the next generation of G-Sync is set to address motion blur through a feature called Pulsar. FreeSync achieves similar synchronization without a hardware module by using the VESA Adaptive-Sync protocol.

For users who see tearing, Engadget suggests trying adaptive sync first if the monitor supports it. With G-Sync, a common setup is to enable V-Sync in the Nvidia app alongside G-Sync and cap the frame rate at about 3 frames per second below the monitor's maximum refresh rate. With FreeSync, standard V-Sync should be left off, but if tearing persists, enabling V-Sync is an option. The main limitation is hardware support: a monitor must support FreeSync or G-Sync out of the box. G-Sync also requires a compatible Nvidia GPU. FreeSync is made by AMD but also works with Nvidia GPUs.

If a monitor or game is incompatible with variable refresh rate, V-Sync can serve as a backstop. It works best when the PC can maintain a steady frame rate at or above the monitor's refresh rate. Users can start by enabling V-Sync inside a game; if the game does not support it or implements it poorly, they can force it through the graphics card control panel. There is usually no reason to enable it in both places. According to Engadget, if no screen tearing is visible, V-Sync can be left off.