Variable refresh rate (VRR) is a technology that allows a monitor to synchronize the refresh rate with the output of any device connected to it, reducing the appearance of visual artifacts, screen tearing, and frame pacing problems. When support for VRR first appeared on graphics cards and monitors, it tended to connect with specific manufacturers: G-Sync for Nvidia and FreeSync for AMD. But in 2014, VESA incorporated native Adaptive-Sync support into DisplayPort 1.2a based on technology provided by AMD and is now a standard compatible with graphics processors from all three major manufacturers: Intel, AMD and Nvidia. Nvidia and AMD already have certification tests for their own standards Both Nvidia and AMD have long offered their own certification schemes for VRR displays using their own proprietary standards, but it is more of a wild west when it comes to the open Adaptive-Sync standard. When Nvidia began testing Adaptive-Sync screens in 2019 as part of the G-Sync Compatible initiative, only 5.56 percent of the models it tested were truly successful. Either they did not offer a fairly wide range of refresh rates or they had other image quality problems, such as flicker. The new VESA certification is designed to offer similar assurances about Adaptive-Sync support for a monitor or laptop. But unlike Nvidia or AMD certifications, it is an open source industry standard and its testing criteria are public. “There are obviously proprietary standards from GPU vendors, but they never revealed the full extent of their testing,” Roland Wooster, an Intel engineer and chairman of the VESA task force that created its new test, told me in a Zoom dial. . Take a look at the Nvidia website, for example, and you will see that it says that a screen must pass over 300 tests to win a G-Sync logo, but it is not known exactly what these tests are. And this has created some confusion over the years, especially when it comes to criteria like “Lifelike HDR”. “They never revealed the full extent of their tests” With its certification, VESA tests raw Adaptive-Sync performance, instead of GPU-specific standards, such as FreeSync or G-Sync. For this reason, VESA expects that its certification logos will often be placed next to those of the specific manufacturer. A G-Sync logo tells you how a monitor will work with an Nvidia GPU, but a VESA AdaptiveSync logo can tell you how a monitor with any Adaptive-Sync-enabled source will work. Importantly, VESA Adaptive-Sync technology is only available for its own DisplayPort standard, which is used on monitors and laptops (including whenever you stream video via USB-C). Unfortunately, this is not going to help you choose one of the growing TVs that offer VRR support via HDMI 2.1, where the standards are even wilder. But in addition to being more public, Wooster suggests that VESA’s new certification standard has screens at a higher level than these specific vendor certifications. “We’ve seen some screens that meet these flicker-certified, jitter-certified screens that do not meet the gray-to-gray specifications we have here,” he says. In a subsequent email, he tells me that he expects significantly less than half of the Adaptive-Sync monitors on the market to meet VESA standards, similar to those found by Nvidia when it introduced its own certification for Adaptive-Sync monitors. According to VESA certification, there are two conformance logos that screens can win. MediaSync is for screens that you can use to watch videos or use to create content, while AdaptiveSync is for gaming screens. If their device passes these tests, manufacturers are allowed to affix the relevant logos on the box, product website, or anywhere it thinks potential customers may see. A screen that fails in testing may not use the logo, but manufacturers do not have to publicly disclose a failure. MediaSync logo focused on video playback.Image: VESA The AdaptiveSync logo is intended for game screens.Image: VESA The first of the two logos is called MediaSync. The focus here is to ensure that screens are capable of playing video content – with less than 1ms jitter – in each of the 10 major international frame rate standards (23,976, 24, 25, 29.97, 30, 47,952, 48, 50, 59.94 and 60 fps – where 23,976 was often typical of movie content in America). Sounds like a simple question, but 24 fps content can be a real hassle when playing on 60 Hz screens because the frames are not evenly spaced at the refresh rate. Three-two pull down was a common way to deal with the problem (where the first frame appears twice, the second three times, the third twice, etc.), but it can create an unpleasant tremor. The MediaSync logo means that a monitor can use Adaptive-Sync to avoid such problems. The second is the AdaptiveSync logo, which is aimed at high-refresh game screens. Thus, for beginners, a screen with the AdaptiveSync logo should be able to operate at a maximum refresh rate of 144 Hz or higher in native resolution at the default factory mode, and the adaptive refresh rate should be able to drop to 60 Hz. This may not seem like a very low floor, but Wooster explains that if your frame rate drops below 58 fps, for example, then a monitor should use a doubling frame to bring it to 116 fps and return it to adaptive synchronization range. If a screen can reach 144 Hz, then you will see a “Display 144” box to the right of the certification logo, but Wooster tells me that this number will reflect whoever is a monitor’s maximum refresh rate – whether it is 144, 240 or 360 Hz – in native resolution. A thorough and open approach It is not enough just to be able to display this range of frame rates. To be certified, a monitor must be able to do well. This means that a flicker level is not visible to the naked eye, even when the frame rate of a screen changes rapidly. It means that the frames do not fall – something that can happen when a monitor provides input with support for higher frame rates than a panel actually supports. VESA also follows a detailed approach to how it measures response time or the time it takes to update screen pixels. Across the industry, it is common to see this expressed as a “gray to gray” response time, or about the time it takes for a pixel to change from one shade of gray to another. If the response times are too slow, the screens may display “ghosts” where the remnants of a previous image are still visible on the screen as the pixels find it difficult to keep up. To obtain an AdaptiveSync logo, a monitor must have a response time of less than 5 ms. 5 ms may seem high compared to the 1 ms response times that many manufacturers claim their screens can do. But in real-world tests, such as those performed by Rtings, response times are generally much higher than 1ms. Rtings generally classify any response time below 6 ms as “good value”. Manufacturers prefer to make these claims for 1 ms response times because they are not as rigorous in their testing as independent reviewers such as Rtings or VESA test centers. Some manufacturers, says Wooster, may make various changes from gray to gray and then choose the best result. Others may benefit from the fact that a warmer panel can respond significantly faster than a cold one. Overdrive can be used to achieve faster response time on paper, but at the expense of ugly visual artifacts. The first certified monitors will be added to the VESA list today VESA’s solution is to measure a variety of different transitions from gray to gray (20 in total) and get an average, instead of choosing the best result. The tests are performed at an ambient temperature between 22.5 and 24.5 degrees Celsius (72.5 – 76 Fahrenheit). The screens are given time to reach a constant temperature first and limits are set on the exceeding and falling of a screen that can still display and pass. Wooster declined to say how many VESA members it expects to pay for their devices to eventually receive MediaSync or AdaptiveSync certification (the charge is the same whether the screen goes through or fails), but the first certified screens will appear on the VESA website today. Highlights the number of devices currently bearing one of VESA’s HDR certifications as an example of the amount of screens and laptops we may eventually see bearing the new AdaptiveSync logos. Given the awesome list of VESA members from across the monitor industry, these little orange and blue logos could quickly become a hallmark of quality when you buy your next monitor or laptop.
