A torn image looks like someone sliced the screen with a ruler. Variable refresh rate makes the monitor wait for the graphics card instead of the other way round.
The short answer
Variable refresh rate (VRR) lets a display adapt its refresh timing to the frames the graphics card actually delivers [1]. Without it, a GPU that has not finished the next frame in time must either repeat the current frame, which causes judder, or show a partly rendered frame, which causes tearing [1]. VRR exists as VESA Adaptive-Sync over DisplayPort and as HDMI VRR; AMD FreeSync builds on both, and NVIDIA calls validated displays G-SYNC Compatible [4][6]. Our assessment: on a gaming monitor, turn VRR on in both the monitor and the GPU software, because it is often off by default.
How it works
- The source sets the pace. With HDMI VRR, a console or PC delivers frames as fast as it can, and the display waits until the next frame is ready instead of refreshing on a fixed clock [1].
- A range, not a free-for-all. Every VRR display has a minimum and maximum refresh rate. VESA's AdaptiveSync Display logo, aimed at gaming, requires a range from at most 60 Hz up to at least 144 Hz; the MediaSync Display logo for video requires at most 48 Hz up to at least 60 Hz [3].
- Tested logos. VESA launched its Adaptive-Sync Display Compliance Test Specification in May 2022 with more than 50 test criteria, including flicker and jitter [2]. The AdaptiveSync logo carries a number such as 144 or 240, the highest frame rate reached in Adaptive-Sync operation at the display's factory default resolution [2][3].
- FreeSync tiers. AMD FreeSync uses DisplayPort Adaptive-Sync and HDMI VRR [4]. AMD's tier table for monitors lists FreeSync with at least 144 Hz and FreeSync Premium with at least 200 Hz below 3,440 horizontal pixels (at least 120 Hz from 3,440); Premium Pro adds HDR [4]. AMD also says that VESA AdaptiveSync certification is not the same as FreeSync certification [4].
- Below the range. Low framerate compensation (LFC) shows each frame several times when the game drops below the display's minimum. AMD's example: a 60 to 144 Hz monitor runs a 40 fps game at 80 Hz by doubling each frame [4]. Our reading: above the top of the range, VRR cannot help, and the GPU falls back to your V-Sync setting.
- NVIDIA. G-SYNC Compatible monitors support VRR on GeForce 10 series and newer over DisplayPort and on GeForce 30 series and newer over HDMI 2.1 [6]. An older NVIDIA support answer names the GeForce GTX 16 and RTX 20 series and newer for VRR over HDMI on displays with HDMI 2.1 VRR [5], so NVIDIA's own pages disagree for those two series. Some Adaptive-Sync monitors ship with VRR switched off or with the DisplayPort mode set to 1.1; it has to be 1.2a or higher [7].
A practical example
You connect a new 165 Hz monitor via DisplayPort to a GeForce card. First switch on the variable refresh function in the monitor's on-screen menu, and check that its DisplayPort mode is not set to 1.1 [7]. Then open the NVIDIA Control Panel, go to Display, "Set up G-SYNC", tick "Enable G-SYNC, G-SYNC Compatible" and apply [5]. If the monitor is not on NVIDIA's list, VRR may work, work partly or not at all [5]. This is a generic walk-through, not a test on our own hardware.
Checklist
- Turn VRR on in the monitor menu first; it may ship disabled [7].
- Set the monitor's DisplayPort mode to 1.2a or higher [7].
- Enable G-SYNC Compatible or FreeSync in the GPU software [4][5].
- Check the VRR range and whether the monitor supports LFC before you buy [3][4].
- Prefer DisplayPort on GeForce cards older than the 30 series, because NVIDIA's pages disagree on HDMI VRR for the GTX 16 and RTX 20 series [5][6].
- Compare logos carefully: AdaptiveSync, FreeSync and G-SYNC Compatible are separate certifications [4][6].