What is VRR? Variable refresh rate explained

What is VRR? Variable refresh rate explained Many people wonder what is VRR?  It's one of many acronyms that are floating around TV features these days., But you'll want to understand it to make sure you're fully informed when shopping for a new TV, especially if you plan to use it to play games on an Xbox Series X / Xbox Series S or PS5. VRR or, what is variable refresh rate called, is a key feature to achieve a smooth and artifact-free image when playing games, which ensures a sharp image for offline and competitive games. But How does it work and how much difference does it really make? You will find all the answers in the guide below.

What is VRR?

VRR's main job is to eliminate screen tearing when gaming. Tearing is a kind of visual problem, where your TV picture flickers in the middle of the frame before continuing as before. But what is really going on here? Screen tearing occurs when your TV's picture update is out of sync with the speed to which your console or the graphics card of your PC that delivers images. You end up with half an image on the screen to see, for example, the top half of the screen showing one image and the bottom half the next. This happens because TVs do not instantly update the entire image on the screen. A monitor's controller quickly scrolls the screen, usually up and down, updating the state of each pixel. It happens too fast for our eyes and brain to notice, until it causes a visual aberration. The tearing becomes noticeable when, for example, you're using a 60Hz TV and your game's frame rate is between 45fps and 60fps. This is especially evident in fast-moving games like first-person shooters. Turn around quickly in the game, and the difference between the information on the screen can be very different from one image to another.

It's a shocking look.

VRR eliminates this by synchronizing the refresh rate of the screen with that of the console output. No more tearing, no performance hit because the console or PC drives the beat, not the screen. The last of us 2 The Last of Us Part II (PS4) (Image credit: Sony / Naughty Dog)

VRR over HDMI 2.1

This concept of updating the screen to match the rendered images is nothing new, but the technology has recently improved and become much more accessible. VRR is now part of the HDMI 2.1 standard, which is also supported by eARC, and is a feature of the next-generation Xbox Series X, Series S, and PS5 consoles. Frame sync isn't just for PC gaming fans anymore, and VRR supports resolutions up to 4K and frame rates up to 120fps, which is the current limit on what these most popular consoles and TVs can produce. VRR over HDMI 2.1 is an important standardization of the process, because before that we had to rely on G-Sync and FreeSync. These are proprietary techniques from Nvidia and AMD, and they came long before HDMI 2.1. While you do get G-Sync on LG OLED TVs, for example, it's not as prevalent on smart TVs like VRR.

VRR support: What TVs, graphics cards and consoles do they have?

Well, we already know that the latest Sony and Microsoft consoles support VRR. But what else does he do? Perhaps surprisingly, Xbox One S and Xbox One X do too. They use AMD FreeSync, since they have AMD graphics processors, but they have also been updated to support VRR over HDMI. Tech-savvy ones might wonder how this is possible when the Xbox One X and One S aren't HDMI 2.1 consoles. This is where things get a bit more confusing. HDMI 2.1 is not a single standard, but rather a collection of technologies. It's a bit like 5G in this sense. Some HDMI 2.0 devices support VRR over HDMI, but the lower bandwidth of HDMI 2.0 means it runs at up to 60Hz instead of 120Hz on Xbox One X. This fragmentation of HDMI is also the reason why some of the newer HDMI 2.1 TVs do not support VRR; You don't buy it just because it has an HDMI 2.1 connector. This will be less of a headache by the end of 2021, when VRR over HDMI is likely to become a standard feature of mid-range and higher-end TVs. But since this is a support tile right now, Here's a look at the most popular high-end TV series and consoles/GPUs that support VRR.

Consoles

Graphics cards

TVs

What does this tell us? High-end Samsung and LG TVs are by far the best when it comes to next-gen console features. However, there are other factors that complicate it. 48-inch LG CX OLED LG CX OLED (2020) (Image credit: LG)

Problem One: Refresh Rate Range

Every VRR-compatible TV or monitor has an operating range, the variety of refresh rates at which it can operate while using VRR. It's usually something like 40-120Hz, like on the wonderful LG CX OLED. This means it won't work for games that prioritize visual quality over frame rate and aim for 30fps performance. However, there is a solution. Some VRR displays have a feature called LFC (Low Frame Rate Compensation). This allows the screen to refresh at twice the rate of the rendered frames. So they stay in sync, but the TV works twice as hard. This is important because if the Xbox Series X and PS5 are marketed as "120fps" consoles, 30fps gaming will likely still work. Because? By aiming for a lower frame rate, and perhaps even a resolution below 4K, developers can use more of a console's power for advanced ray-traced lighting, texture, or shadow effects. They are likely to improve immersion more than a high frame rate in slower-paced adventure games.

Problem Two: AV Receivers

We have bad news. You may also need to upgrade your home theater receiver if you have a traditional surround sound setup as it must also support VRR. And unless you have a new receiver, that's definitely not the case right now. Fortunately, there is a solution. You can connect your PC or game console directly to your TV and use the TV's optical audio output or an HDMI ARC or eARC connector to send the audio to your receiver. ARC and eARC then transform one of your TV's HDMI inputs into an audio output. eARC (Enhanced Audio Return Channel) is the better of the two. Its higher-bandwidth connection allows very high-speed formats like Dolby TrueHD and DTS-HD to pass through. AV Receiver (Image credit: LaComparacion)

Wait, what about FreeSync, V-Sync and G-Sync?

For fully understand why VRR over HDMI 2.1 is special, it's a good idea to look back at the forerunners of this technology. Let's start with V-Sync, the original solution to image tearing. V-Sync changes things up by running the GPU at the speed of the display's refresh rate, which traditionally would have been 60Hz. The GPU multiplies the frame delivery to match the display's capability. The tearing is resolved, but similar visual issues appear if the renderer speed can't keep up with the screen refresh rate. You will see points where the same image is displayed two or more times in a row, resulting in jerkiness caused by what is intermittent halving (or a quarter of the frame rate). This issue was fixed with Adaptive V-Sync, introduced by Nvidia in 2012. It simply disables V-sync when the frame rate drops below the monitor's refresh rate. Neither method was ideal, leading to the introduction of Nvidia G-Sync in 2013 and AMD FreeSync in 2015. These are very similar to the VRR implementation in HDMI 2.1, so the screen changes its behavior instead of the PC.

VRR OLED problem

Now that we've given you an insight into the history of this technology, we need to take a step back to give you a more technical look at what's going on behind the scenes. Somehow VRR, G-Sync and FreeSync don't really change the behavior of the screen as much as you might imagine. Much of the screen's behavior is always determined by its maximum refresh rate. Take a 120 Hz television as an example. You can update your screen image 120 times per second, or once every 8,3 milliseconds or so. Each interval is a window of time in which the TV can draw an image, and these stay the same regardless of the refresh rate that VRR seeks to emulate. The screen just waits for the frame to complete and then puts it in one of those 8,3ms windows.Samsung q80t Samsung Q80T QLED TV (2020) (Image credit: Samsung) There aren't any major issues here with LCD TVs, because of how they work. The state of the pixels on an LCD screen and the light that illuminates them are somewhat independent. LCD screens, including Samsung QLEDs, have LED backlight arrays that sit behind the pixels or on the sides of the screen. OLED TVs have light emitting pixels and this seems to affect their performance when using VRR. Here are some impressions from writer John Archer, often of TechRadar, at Forbes: “The biggest problem, and one that affects both the 2019 and 2020 LG OLED sets, is that when the VRR is turned on, the image experiences a brightness/gamma shift that makes dark areas in games look grayer from the transformed VRR. I saw it myself recently on an LG OLED48CX. " Changing the gamma curve could be a technique used to moderate screen brightness and prevent flickering that VRR can cause on certain panel types.. Oh, and some LG OLED owners have also complained about VRR-related flicker. What does it mean? The perfect OLED TV for VRR gaming has yet to be created. But you can be sure that it is ongoing. Today's best LG OLED TV deals

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