Vsync, short for Vertical Synchronization, is a graphics technology designed to sync a games frame rate with the refresh rate of a gaming monitor. It works by limiting the GPUs frame rate output to the monitors refresh rate, which prevents screen tearing. Screen tearing happens when different parts of the screen display different frames at the same time, which can lead to visual artifacts resembling a horizontal split in the display. When Vsync is enabled, the graphics card waits for the monitor to finish displaying a frame before sending it another one, which reduces input lag, the delay between when you move your mouse or press a key and when the action appears onscreen.

Vsync can make games look smoother and more visually appealing, and it also reduces input lag. However, it can reduce a computers performance and may cause stuttering or input lag in certain situations. Vsync only helps with screen tearing and does not improve resolution, colors, or brightness levels like HDR.

Whether to turn Vsync on or off depends on personal preference and the specific game being played. Serious gamers may prefer not to enable Vsync because it can reduce performance and cause input lag or stuttering. However, Vsync is an excellent option for gamers who are dealing with mismatched frame rates and refresh rates, and it is also great for gamers who prefer running older games on their PC via emulators.