Variable refresh rate (VRR) technology is designed to improve your gaming experience by reducing the amount of screen tearing that occurs when your game's frame rate doesn't match your display's refresh rate. Until a few years ago, VRR technology was only supported on gaming monitors. In 2018, Samsung became the first brand to support VRR technology on their TVs, with the addition of FreeSync VRR support to their high-end QLED TVs. The first few TVs with FreeSync had limited usefulness, though, as they only worked with PCs with AMD graphics cards and a few consoles, including the Xbox One X.
The announcement of HDMI 2.1 changed this, though, and added support for the open VESA Adaptive Sync standard over HDMI, also known as HDMI Forum VRR. Originally only supported by the Xbox One S and the Xbox One X, NVIDIA added support for Adaptive Sync in October 2019. This new feature works with any GeForce RTX or GeForce GTX 16-Series GPU and requires a TV that supports HDMI Forum VRR. NVIDIA has grouped this new feature into their existing G-SYNC Compatible certification program.
G-SYNC compatibility is important if you have an NVIDIA GTX-16 series, RTX 20-series, or RTX 30-series graphics card and would like to buy, or already own, a TV that supports HDMI Forum VRR. It'll allow you to enable G-SYNC on your PC, even though your TV doesn't natively support it. Variable refresh rate technologies like G-SYNC aim to reduce tearing, which occurs when the frame rate from your source fluctuates, creating a mismatch between the rate your screen is refreshing and the number of frames coming from the source. G-SYNC reduces tearing by adjusting the refresh rate of your TV to match the frame rate your source is sending. It's especially noticeable if your graphics card can't maintain a high frame rate in graphically-intense scenes or when switching out of pre-rendered cinematic cutscenes.
We test Adaptive Sync on a custom-built PC with an RTX 3080 GPU. We use NVIDIA's Pendulum G-SYNC demo to test for tearing, stuttering, screen blanking, and other artifacts. We disable V-SYNC, as we want to ensure that the display is adjusting its refresh rate to match the source content. We then enable G-SYNC from the pendulum demo, and, starting at the TV's native refresh rate and resolution, we gradually decrease the frame rate, looking for any issues. From there, we gradually increase the frame rate until we start seeing tearing or other issues. The results of both of these tests give us the effective variable refresh rate range. We repeat the test at least twice to confirm our findings.
We run the same test with the resolution set to 4k, 1440p, and 1080p. Some TVs have wider supported ranges at lower resolutions, especially TVs that don't support HDMI 2.1 bandwidth. Older TVs that don't support HDMI 2.1 bandwidth are usually limited to a 60Hz refresh rate with a 4k signal, but some of them support a 120Hz refresh rate with 1440p and 1080p signal.
We also playtest each TV with a few games, including Destiny 2. During our playtesting, we check for any tearing, especially in scenes with low frame rates and when the game transitions from pre-rendered cutscenes to in-game, as this sudden change in frame rate can cause excess tearing on some displays.
We use the results of this test to assign a result based on how well the TV supports NVIDIA's Adaptive Sync implementation. The possible results are:
Unlike monitors, which support G-SYNC Compatible mode with 10-Series graphics cards, G-SYNC Compatible mode on TVs requires at least a 16-Series graphics card. On most TVs, you'll also have to enable FreeSync or Adaptive Sync for it to work. Some newer models have separate toggles for FreeSync and G-SYNC Compatible.
To enable FreeSync, you must first select "G-SYNC Compatible" from the Monitor Technology setting under NVIDIA Control Panel. Once this setting is enabled, you should see a new option, Set up G-SYNC, appear under the Display menu. From there, you can enable G-SYNC for either full-screen mode or both full-screen and windowed mode.
NVIDIA updates their list of supported TVs and Monitors frequently; you can see the current list on NVIDIA's website. If your TV is supposed to be supported but isn't working, check the following:
This test is by no means exhaustive, and your results may vary depending on the specific games you're playing and your specific graphics card. Some tearing can still occur on most TVs, especially during rapid refresh rate changes. This could cause a few seconds of tearing when changing from pre-rendered cutscenes in games to the in-game engine or if the game suddenly slows down significantly.
We hope to expand this test in the future; let us know in the discussions if you have any suggestions on things we could check.
TVs are becoming more and more advanced, with impressive new gaming features, including G-SYNC Compatibility. New technologies like HDMI Forum VRR and G-SYNC Compatibility blur the line between TVs and monitors, and TVs often work with certain technologies without being officially certified. We check for G-SYNC Compatibility on all TVs and test the range of refresh rates the TV supports. Understanding the range a TV supports will give you a better idea of what to expect when gaming with certain sources. The addition of Adaptive Sync to NVIDIA's drivers is a welcome change and represents a significant policy shift at NVIDIA.