Refresh rate: Hertz and variable refresh rate

In short: The refresh rate says how often a monitor redraws the picture per second; variable refresh rate adapts it to the graphics card’s frame rate.

In more detail: A monitor with 60 Hz redraws the picture 60 times per second, one with 144 Hz 144 times. Higher values feel smoother, especially with fast movement in games or when scrolling. The graphics card must deliver enough frames per second (fps) for this.

In Depth

Hertz and frame rate

The refresh rate (Hz) is a property of the monitor; the frame rate (fps) describes how many images the computer calculates. Usual are 60 Hz for office work, 120 to 165 Hz for games and above 360 Hz for competitive monitors. A 60 fps image on a 144 Hz monitor is displayed several times and does not look smoother than on 60 Hz. The difference between 60 and 144 Hz is clearly visible; the steps above that get smaller.

Tearing and V-Sync

If graphics card and monitor are not in step, an edge appears in the middle of the picture (“screen tearing”) because two partial frames are mixed. V-Sync waits for the monitor’s timing and prevents this but can cause lag and stutter if the frame rate falls below the refresh rate.

Variable refresh rate

With VRR the monitor follows the graphics card: it displays a new frame as soon as it is ready, within a range (for example 48 to 144 Hz). There is no tearing and less stutter. The names: G-Sync (NVIDIA), FreeSync (AMD), Adaptive-Sync (VESA standard over DisplayPort) and HDMI VRR. Modern consoles and TVs support HDMI VRR.

In practice

Set the refresh rate in the operating system’s display settings; after connecting it is often initially at 60 Hz. The cable must offer enough bandwidth (DisplayPort or HDMI 2.x). Higher rates need more power. For smooth scrolling and mouse pointer, 120 Hz is worthwhile in everyday use too.

See also: Monitor, DisplayPort, HDR and monitor brightness