Hardware

VSync vs GSync Compared

Visual artifacts can be quite annoying. Who wants to see distorted images when playing video games or movies? One very common artifact which can disrupt your gaming experience is screen tearing. Screen tearing is a visual nuance that is caused by a mismatch between the GPU’s frame rate per second (FPS) and the display monitor’s refresh rate. When screen tearing occurs, one part of the screen becomes misaligned with the other part, usually split by a horizontal line. Sometimes, there can be more than just one tearing point, resulting in a more distorted image.

Various visual-enhancement technologies have emerged to eliminate visual artifacts such as screen tearing for a flawless visual experience. GPU developers like Nvidia have tweaked settings and hardware to synchronise the FPS of the GPU and the refresh rate of the display for smoother visuals. When screen tearing has become a popular issue among gamers, developers have started working on VSync, which has effectively removed screen tearing. The name does not directly suggest what VSync actually does, so most gamers tend to leave the setting as is. Let’s understand the technology behind it and how it works to help you decide whether to turn this feature on or off.

Vertical Synchronization (VSync)

The GPU throws image frames to the monitor and processes these frames to render images. The process is done rather rapidly so that it’s not obvious to our naked eyes. What we see are just the final moving images or videos. If the GPU and display are in-sync, the whole process is seamless and the images stunning. However, that is not always the case.

The display’s refresh rate is measured in Hz, and the ratio of FPS to the refresh rate is usually 1:1. So your 60-FPS GPU can work well with a 60Hz display. However, if the GPU’s FPS exceeds the display’s refresh rate, this is when screen tearing occurs. If your GPU is 100 FPS, for example, but your display is only 60Hz, it will bottleneck at the display when the GPU throws a new frame to it while it’s still processing the current frame, showing two frames at once. The resulting image then appears like it’s being torn or split into two or more parts, thus screen tearing.

Vertical Synchronization or simply VSync is a graphics technology that adjusts the GPU’s FPS to synchronize with the display’s refresh rate to mitigate screen tearing. It forces the GPU to lower its frame rate to match or be lower than the display’s refresh rate. VSync combines double buffering and page flipping to stop the GPU from sending frames to the display while it’s still processing the current frame. VSync is a flexible visual setting compatible with any display. In addition, most graphic card drivers contain GPU settings, but it’s also already included in the settings of most games, so you can enable the feature only in specific games. VSync is an effective way to prevent screen tearing; however, VSync comes with its own downsides.

Since the GPU’s FPS has to be reduced to match the display’s, the GPU’s performance will not be fully optimized, limiting it from reaching its peak performance. Your GPU will be somehow downgraded, and its full potential will be put to waste. Moreover, while VSync eliminates one problem, it introduces another one – input lag. Input lag is the delay between the key you press on your keyboard or the button you press on your mouse or controller and the screen output. In VSync, the GPU is forced to hold the frames it has already rendered in its buffer while waiting for the monitor to finish refreshing. Input lag’s bothersome effects on video games are evident in high precision and fast-moving portions. Another issue introduced by VSync is stuttering which happens when the GPU’s FPS falls lower than the monitor’s refresh rate. This usually happens when games reach graphics-intensive parts, which causes a significant drop in FPS, usually by half. So if VSync has adjusted the GPU’s FPS to 60 to match the monitor’s 60Hz refresh rate, once the game reaches a graphics-intensive point, the FPS will drop to 30 FPS, resulting in stuttering on the images.

VSync does a great job in preventing screen tearing but does cause other graphics issues, which are just as equally disruptive to the gamer’s experience as screen tearing. To resolve the issues caused by VSync, Nvidia brought in a syncing technology that will solve all these issues altogether.

Nvidia’s GSync

Nvidia has built powerful GPUs, but their performance will not be optimized once VSync is enabled. With that, Nvidia has introduced a hardware-based syncing technology that removes screen tearing and mitigates all the resulting issues of VSync. Unlike VSync, Gsync adjusts the display’s refresh rate to handle the frames that GPU throws at it regardless of the speed.

Nvidia replaces the scaler board, the controller in the displays, with their own module that controls all the display’s activities and primarily changes the display’s refresh rate to match the GPU’s FPS. The module contains a 768MB of DDR3 that holds the previous frame so it can be compared to the incoming frame, consequently reducing input lag. Nvidia’s driver takes full control of the Nvidia’s module on display. The GPU can reach its max FPS if necessary, and the display’s refresh rate will variably adjust to it, eliminating screen tearing, input lag, and stuttering.

GSync is a versatile tool, but it comes with caveats. For one, it’s not royalty-free. All displays with GSync’s module carry the GSync banner. Another caveat is it’s not compatible with all Nvidia GPUs. Desktops connected to a GSync monitor must have a GeForce GTX 650 Ti BOOST or newer and must use an R340.52 or higher graphics driver. Similarly, laptops connected to GSync displays must have GeForce GTX 980M, GTX 970M, or GTX 965M GPU or newer GPUs and must use an R340.52 or higher graphics driver. The same set of GPUs is required for laptops with a built-in GSync display, but the driver should be R352.06 or higher.

GSync has GSync, GSync Ultimate, and the newest GSync Compatible. All three classes have been validated by Nvidia with ‘no artifacts’. GSync and GSync Ultimate displays have GSync modules installed, while GSync Compatible displays do not contain Nvidia’s module but support variable refresh rate, which has been tested and validated by Nvidia. GSync has been certified by Nvidia with +300 tests and is supported by 24-38-inch displays. GSync Ultimate, on the other hand, has undergone the same +300 tests but with a string of other features like 4K support, 1000 nits brightness and support for wider displays (27-65 inches). The quality GSync displays come at a hefty price tag, with a higher price tag for GSync Ultimate displays. Budget gamers can settle with the cheaper alternative, GSync Compatible.

The Verdict

VSync and GSync all work for the good of image quality specifically to eliminate screen tearing, but VSync comes with a price – input lag and stuttering. GSync eliminates all these issues and more but comes at a higher cost. VSync is more flexible than GSync, with no restrictions on what displays to use but will limit the GPU’s performance to match the display’s refresh rate. GSync, on the other hand, offers more versatility and higher quality displays without compromising the GPU’s performance and will certainly be worth the higher price tag. If you’re fond of playing triple-A games, GSync or GSync Ultimate will be a worthy investment, but a GSync Compatible display will be a satisfying alternative if you’re on a budget. If you play games that are not graphics-intensive but suffer from occasional screen tearing, enabling VSync will improve your gaming experience without breaking the bank.

About the author

Glynis Navarrete

A freelance blogger who loves to write about anything related to technology. Born and raised in the Philippines and worked in Singapore for eight years as Technical Support for a wide range of IT equipment. Took a dive into the world of freelancing and now enjoying doing what I’m passionate about while not losing touch with technology.