Nvidia G-Sync is a type of adaptive sync technology for displays, namely PC monitors and gaming laptop screens. The feature helps displays fight screen tearing, stuttering and juddering when you’re gaming, particularly at high framerates. G-Sync only works when the display is connected to a PC using a compatible Nvidia graphics card.
Screen tearing is an unwelcome effect on the image’s display when gaming (see photo above). It’s the result of the game’s framerate (the rate at which image frames are displayed) not matching the monitor’s refresh rate (the frequency at which a display’s image is refreshed). G-Sync fights this for refresh rates up to 240Hz, depending on the monitor; however, for displays with 4K resolution (aka UHD), that number drops to 144Hz (aka UHD). Tearing is a result of the graphics card outputting images at faster rate than the monitor.
G-Sync matches the display’s refresh rate to your Nvidia graphics card’s render rate, so you see images right when they’re rendered, while also fighting input lag. There are three types of G-Sync: regular G-Sync, G-Sync Ultimate and G-Sync Compatible. The former two use Nvidia's proprietary processor and also include options for variable overdrive, which predicts when the next frame will come and adjusts the monitors overdrive to fight ghosting artifacts
Check out Nvidia’s video below for an idea of what G-Sync looks like:
G-Sync vs. FreeSync
FreeSync is AMD’s answer to G-Sync. So to use AMD’s take on adaptive sync, your computer must use an AMD graphics card.
There some other differences between the two technologies, though. When it comes to 4K monitors, FreeSync maxes out at 120Hz, while G-Sync can go to 144Hz. Finally, there are some FreeSync TVs on the market right now, but no G-Sync ones.
Additionally, unlike with FreeSync, to use G-Sync ir G-Sync Ultimate in their product, monitor makers have to pay for Nvidia's proprietary chip, which replaces the scaler they'd typically buy. AMD FreeSync is built on an open standard. As a result, G-Sync monitors generally cost more than FreeSync monitors. And when we checked out monitors at the CES tech show this January, we noticed more FreeSync monitors coming out this year than G-Sync. This is probably due to the cost implications G-Sync presents to both display vendors and buyers. But this could change, thanks to G-Sync Compatible Monitors.
G-Sync Compatible Monitors
In January 2019, Nvidia started testing and approving specific monitors with other types of variable refresh rate technology, including FreeSync ones, to run G-Sync. They call these monitors "G-Sync Compatible." Confirmed by our own testing, formerly non-G-Sync and/or FreeSync-only monitors can now successfully run G-Sync with an Nvidia graphics card, the proper driver and a few caveats. Some things Nvidia confirms you can't do with G-Sync Comptaible displays versus regular G-Sync displays are ultra low motion blur, overclocking and variable overdrive. Of course, FreeSync monitors dubbed G-Sync Comptaible can still run FreeSync if your PC uses an AMD graphics card.
You can find the full list of G-Sync Compatible monitors at the bottom of Nvidia's webpage. You can also check out our step-by-step instructions for how to run G-Sync on a FreeSync monitor, which includes details on the small number of limitations you'll face.
For a deeper exploration of the performance differences between G-Sync and FreeSync, see our AMD FreeSync vs. Nvidia G-Sync article.
G-Sync Ultimate Monitors: G-Sync and HDR
To run G-Sync with HDR content, you need a monitor dubbed "G-Sync Ultimate," rather than plain G-Sync. Unlike regular G-Sync, G-Sync Ultimate displays are certified for ultra-low latency, multi-zone backlights, DCI-P3 color gamut coverage, 1,000 nits max brightness with HDR video or games and to run at its highest refresh rate at its max resolution -- all thanks to an "advanced" Nvidia G-sync processor. If you don't want to have to pick between G-Sync and HDR, a G-Sync Ultimate monitor is necessary.
G-Sync monitors: What you’ll need
You can find a full list of G-Sync monitors here.
To use a G-Sync monitor, you must use a Windows PC with a GeForce GTX 650 Ti graphics card (it can be Nvidia or third-party branded) or higher, along with the proper driver. You can see the full list of GPUs G-Sync supports here. For help picking a graphics card, see our graphics card buying guide.
G-Sync gaming laptops
Some gaming laptops running Nvidia graphics have G-Sync built into the display. They’ll say so on their spec sheet. We’ve reviewed a few, including the Alienware area-51m.
This article is part of the Tom's Hardware Glossary.