Nvidia G-Sync Aims to Eliminate V-Sync and Screen Tearing in One Go

By Wesley Fenlon

Nvidia's spent the last few years building a new piece of hardware for gaming monitors that will put graphics cards in charge of refresh rates.

It's a big news day for Nvidia. The company held a press event on Friday to remind the gaming world that, yes, the Nvidia Shield still exists--you can now get one with free games for $100 off!--and that their GeForce-based recording software, ShadowPlay, is nearly here. ShadowPlay allows gamers to automatically record the last 20 minutes of gameplay, and supposedly the built-in H.264 encoding on Nvidia GPUs will prevent a framerate hit while capturing 1080p footage. The software naturally also supports manual recording, and will have Twitch integration sometime after its initial October 28 beta.

But ShadowPlay wasn't the big news of the day. Neither was Shield. That honor goes to G-Sync, a new piece of tech Nvidia hopes will eradicate screen tearing, stuttering and the need for V-sync, which syncs a video card's framerate to the monitor's refresh rate. G-Sync is a piece of hardware Nvidia built to replace scalers in PC monitors. Instead of trying to tie the GPU to the monitor's locked refresh rate, they're coming at the problem from the other way around--modifying the monitor's refresh rate to match the PC's output.

Image credit: Anandtech.com

Because monitors refresh at 60Hz, there's typically a trade-off involved in using V-sync. It eliminates screen tearing, but you have to be able to render at a rock-solid 60 fps or above, or you get stutter. Without V-sync, you get screen tearing, because the monitor and GPU may be updating the frame at different times. With G-Sync, an Nvidia Kepler GPU will now control the timing of frame updates. New gaming monitors with G-Sync could have variable refresh rates--as an example, Nvidia showed a monitor being pushed to its max of 144Hz. ASUS, ViewSonic, BenQ and Philips are already onboard to use G-Sync in monitors.

Anandtech delved into more detail explaining how G-Sync works, though Nvidia hasn't revealed everything yet. "G-Sync is designed to work over DisplayPort (since it’s packet based), with NVIDIA manipulating the timing of the v-blank signal to indicate a refresh," Anandtech writes. "Importantly, this indicates that NVIDIA may not be significantly modifying the DisplayPort protocol, which at least cracks open the door to other implementations on the source/video card side." Anandtech also came away impressed by G-Sync's demos, which compared it with typical gaming monitors exhibiting the issues of mismatched GPU frame rate and monitor refresh.

Image credit: Anandtech.com

G-Sync will start showing up in monitors in the first quarter of 2014--ASUS' first model, a new version of the 144Hz VG248QE, should cost $399. Nvidia also plans to sell the board separately by the end of the year, and hobbyists can buy current VG248QE models (which run about $280) and install the G-Sync themselves.

After having John Carmack, Johan Andersson and Tim Sweeney come on stage to talk up G-Sync, Nvidia had one more announcement to make: the 780 Ti. AMD's next flagship graphics card, the R9 290X, isn't even out yet, and Nvidia's already retaliating. Nvidia didn't reveal the specs of its new card, but promised a mid-November release, and a new position above the GTX 780 but below the monstrous Titan.