What Is G-SYNC? [The Ultimate Guide]

To prevent screen tearing and stuttering, G-SYNC synchronizes the refresh rates of a display (Hz) to the frame rates of a GPU (FPS). However, What Is G-SYNC?

With compatible graphics cards, the specialized module in gaming monitors with NVIDIA’s G-SYNC technology offers a variable refresh rate for tear-free gameplay.

Are you interested in learning more about G-SYNC monitors and how they differ from G-SYNC Compatible, G-SYNC Ultimate, and FreeSync displays? You’ve arrived at the proper location.

What Is G-SYNC?

If you have a graphics card that is compatible, G-SYNC is a special chip inserted inside a G-SYNC display that gives you a variable refresh rate (VRR) and variable overdrive.

Nvidia’s hardware-based monitor synchronizing technique is called G-Sync. G-Sync mostly eliminates screen tearing by matching the refresh rate of your monitor to the number of frames your GPU produces each second.

Each second, your GPU outputs a number of frames, which when combined provide the appearance of seamless motion. Similar to how your monitor refreshes, your GPU renders new frames while clearing the old ones for your GPU to display. Future frames are buffered by your GPU to maintain smooth operation. The issue is that your monitor’s refresh rate and buffer could become out of sync, leading to an ugly line of two frames stitched together.

V-Sync was created as a remedy. Essentially, this software-based feature compels your GPU to keep frames in its buffer until your monitor is ready to refresh. This fixes the screen tearing issue but creates a new one called input lag. There is a small lag between what is happening in the game and what you see on screen because V-Sync compels your GPU to hold frames that it has previously produced.

Adaptive VSync was the first V-Sync replacement offered by Nvidia. In order to avoid screen tearing, Nvidia’s driver-based solution limited the frame rate to the display’s refresh rate. However, Adaptive VSync unlocked the frame rate while the GPU was having trouble until its performance improved. When the frame rate was steady, Adaptive VSync locked it until the GPU’s performance fell once more.

In 2013, Nvidia unveiled G-Sync, a hardware-based solution. It is based on the Adaptive-Sync technology from VESA, which allows for varying refresh rates on the display side. G-Sync forces your monitor to adjust its refresh rate in accordance with the number of frames your GPU is rendering rather than requiring your GPU to hold frames. That addresses screen tearing and input lag.

Nvidia, on the other hand, employs a proprietary board in place of the traditional scaler board that manages every aspect of the display, including backlight control and picture input decoding. The 768MB of DDR3 memory on a G-Sync board is used to store the previous frame so that it may be compared to the incoming frame. This is done to lessen input lag.

The display’s proprietary board can be completely controlled by the PC using the Nvidia driver. It alters the vertical blanking interval, often known as the VBI, which is the period between when a monitor completes drawing the current frame and when it starts drawing the following frame.

The monitor becomes a slave to your PC when G-Sync is turned on. The display clears the previous image and makes ready to accept the new frame as the GPU rotates the rendered frame into the primary buffer. The display renders each frame as directed by your PC as the frame rate increases and decreases. Images are frequently repainted at wildly varied intervals since the G-Sync board allows various refresh rates.

The three generations of G-SYNC modules are as follows:

• v1 module with DisplayPort 1.2
• v1 module with DisplayPort 1.2 and HDMI 1.4
• v2 module with DisplayPort 1.4, HDMI 2.0, and a cooling fan (some newer modules may feature two or more HDMI 2.0 ports)

How Does G-SYNC Work?

G-SYNC enables your monitor’s refresh rate (Hz) to alter dynamically in response to the frame rate of your GPU (FPS). As a result, there is no discernible input lag penalty (1ms) and all screen tearing is eradicated up to the monitor’s maximum refresh rate.

Therefore, G-SYNC will dynamically modify the display’s refresh rate to 60Hz in order to give you 60 complete frames per second without tearing if you have a 144Hz gaming monitor and 60FPS in a game.

Variable overdrive, on the other hand, will make sure that the pixel reaction time speed is adjusted appropriately, preventing pixel overshoot at low FPS and ghosting at high FPS.

The G-SYNC module also has the benefit of replacing the monitor’s standard scaler, which results in a marginally smaller input latency.

The price and the fact that there are fewer connectivity possibilities because G-SYNC modules lack VGA, DVI, and USB-C interfaces (for DP Alt Mode) are the biggest drawbacks.

On G-SYNC monitors, Picture in Picture and Picture by Picture modes are also not supported.

Older G-SYNC monitors cannot support display scaling because the normal scaler has been removed; however, contemporary graphics cards can handle GPU scaling without any additional lag, thus this won’t be a problem for most users. The more recent models allow for display scaling, although activating the option in NVCP requires messing with CRU.

G-Sync vs. FreeSync

Both FreeSync and G-Sync, AMD’s response to VESA’s Adaptive-Sync technology, open in new tabs (opens in new tab). Similar to how an Nvidia graphics card is required for G-Sync, an AMD graphics card is required for FreeSync.

There are some significant variations. FreeSync works via HDMI and DisplayPort (which also works over USB Type-C), however G-Sync only works with DisplayPort unless you’re using a G-Sync Compatible TV, which is one of the notable differences (more on that below). Nvidia has stated that it is working to change this, though. See our analysis of DisplayPort vs. HDMI(opens in new tab) for additional information on the two ports and which is ideal for gaming.

Our testing has revealed slight differences between the two in terms of performance. Check out our G-Sync vs. FreeSync article(opens in new tab) to see the results and get a more in-depth look at the performance variations.

Even though G-Sync and G-Sync Ultimate both rely on a proprietary Nvidia chip, they are both based on Adaptive-Sync. If monitor manufacturers want their displays to be certified for G-Sync or G-Sync Ultimate, they must purchase this instead of the scaler they would normally purchase. As opposed to G-Sync or G-Sync Ultimate, FreeSync is an open standard, therefore FreeSync displays are typically less expensive. This chip is not necessary for G-Sync Compatible monitors, and many FreeSync monitors are also G-Sync Compatible.

G-SYNC vs FreeSync & G-SYNC Compatible

FreeSync and G-SYNC Compatible monitors lack specific modules, in contrast to G-SYNC.

For a variable refresh rate, they instead rely on VESA’s free and open-standard Adaptive-Sync protocols in DisplayPort and/or HDMI interfaces.

The G-SYNC In essence, a compatible monitor is a FreeSync or “Adaptive-Sync” monitor that has been approved by NVIDIA to function flawlessly with their compatible GPUs.

So what makes G-SYNC unique specifically?

The VRR range of G-SYNC monitors is typically greater than that of FreeSync and G-SYNC Compatible displays, to begin with.

A 144Hz G-SYNC gaming display, for instance, has a VRR range of 30-144Hz, whereas a comparable FreeSync panel often has a dynamic range of 48-144Hz.

A G-SYNC display would alter its refresh rate to 40Hz if your frame rate dropped to that level, however a FreeSync monitor would have to use LFC (Low Framerate Compensation) and double its refresh rate to 120Hz (40FPS x 3) in order to prevent tearing.

The overall gaming experience will be better on a G-SYNC display in this scenario because LFC produces slight stuttering.

G-SYNC monitors offer reduced input lag than FreeSync monitors because, as was already established, the G-SYNC module takes the place of the monitor’s standard scaler.

The absence of a G-SYNC module has advantages such as lower cost and more varied connectivity possibilities.

Is G-SYNC therefore worthwhile?

Well, that depends on the monitor and, if one is available, its FreeSync/G-SYNC Compatible equivalent.

Even though a FreeSync monitor doesn’t offer variable overdrive sometimes, it can still have a very good overdrive implementation and a VRR range that is just as wide as G-SYNC.

Both the finest G-SYNC monitor buyer’s guide, which includes all G-SYNC gaming monitors worth considering, and a separate article comparing popular G-SYNC displays to their FreeSync counterparts are available on our website.

G-SYNC Ultimate

If a monitor includes G-Sync Ultimate, formerly known as G-Sync HDR, it will look better when used with HDR(opens in new tab) content. For HDR monitor suggestions, see our post on how to choose the best HDR monitor.

Nvidia certifies G-Sync Ultimate displays for ultra-low latency, multi-zone backlights, DCI-P3 color gamut coverage, 1,000 nits maximum brightness with HDR video or games, and to run at its highest refresh rate at its max resolution – all thanks to “advanced” Nvidia G-Sync processors. This is in contrast to regular G-Sync. Remember that these screens tend to be BFGDs (large format gaming displays) and are consequently on the more expensive side.

In addition to the dedicated module, gaming monitors with the G-SYNC Ultimate certification also provide HDR (High Dynamic Range) functionality.

But throughout time, the requirements for this accreditation have evolved.

Here are the previous specifications:

Here are the current specifications for G-SYNC Ultimate:

As a result, the first G-SYNC Ultimate gaming monitors, such the Acer X35 and ASUS PG27UQ, provided a superior HDR viewing experience because of their high peak brightness of 1000 nits and multi-zone backlighting (with full-array local dimming).

These days, G-SYNC Ultimate monitors are available with lower 600-nit peak brightness and poorer multi-zone backlights, such as 32 edge-lit local dimming zones from an Acer X35 with 512 zones of FALD.

These displays typically have VESA’s DisplayHDR 600 certification, and they still provide reasonably respectable HDR image quality.

In comparison to SDR or DisplayHDR 400, HDR image quality is clearly improved, but you are only getting a peek of the ‘real’ HDR viewing experience. Some scenes will appear far better than SDR, while others may even appear worse.

In other words, the incredible HDR image quality that G-SYNC Ultimate once promised has been removed. As with the other HDR certificates, it is deceptive.

Check the monitor’s specifications to see if it has an OLED screen or a good full-array local dimming solution with many zones for the best HDR image quality.

Keep in mind that G-SYNC Ultimate was formerly known as “G-SYNC HDR.”

G-SYNC Requirements

You will require a suitable NVIDIA graphics card (GTX 650 Ti Boost or newer) connected via DisplayPort in addition to a G-SYNC monitor in order to use G-SYNC.

Now, more recent G-SYNC monitors, such the Dell AW2721D, LG 38GL950G, and Acer XB273X, also support AMD graphics cards over DisplayPort and provide HDMI-VRR for gaming consoles.

A GTX 1050 or newer graphics card with DisplayPort 1.4 is required for G-SYNC Ultimate.

To identify all G-SYNC and G-SYNC Ultimate monitors that are offered, utilize our G-SYNC monitor list.

You may find a list of all monitors that NVIDIA has designated as “G-SYNC Compatible” at the bottom of the article.

G-Sync Compatible

In 2019, Nvidia began testing and approving particular displays, including those that could run G-Sync while using other Adaptive-Sync technologies, such as FreeSync. These displays are referred to as G-Sync Compatible. Our testing has shown that, despite not having the same chips as a G-Sync or G-Sync Ultimate display, G-Sync Compatible screens can operate G-Sync with the right driver and a few restrictions.

Some activities are prohibited by G-Sync, according to Nvidia. Ultra low motion blur, overclocking, and variable overdrive are compatible screens as opposed to standard G-Sync displays.

The complete list of G-Sync-compatible displays is located at the bottom of Nvidia’s website.

G-Sync Compatible TVs

There are a ton of OLED TVs with the LG brand that are G-Sync compatible as of 2021. They connect over HDMI to a computer with an Nvidia RTX or GTX 16-series graphics card to operate. Additionally, you must adhere to the instructions for downloading the correct firmware (opens in new tab). Nvidia stated that it is trying to increase the number of TVs that support G-Sync over HDMI in the future.

The list of all G-Sync compatible TVs as of this writing is as follows:

• LG 2021 B1 4K series (55, 65 or 77-inch) 
• LG 2021 C1 4K series (48, 55, 65, 77 or 83-inch) 
• LG 2021 G1 4K Series (55, 65 or 77-inch) 
• LG 2021 Z1 8K Series (77 or 88-inch) 
• LG 2020 BX (55, 65 or 77-inch)
• LG 2020 CX (487, 55, 65 or 77-inch) 
• LG  GX (55, 65 or 77-inch) 
• LG 2020 ZX (77 or 88-inch) 
• LG 2019 B9 (55, 65 or 77-inch)
• LG 2019 C9 (55, 65 or 77-inch)
• LG 2019 E9 (55 or 65-inch)
• LG 2019 Z9 (88-inch) 

ULMB & Reflex Analyzer

NVIDIA’s ULMB (Ultra Low Motion Blur) technology, which uses backlight strobing to reduce perceived motion blur at the expense of picture brightness, is also compatible with some (but not all) G-SYNC displays.

Contrary to some other MBR (Motion Blur Reduction) implementations, such as ELMB-Sync by ASUS or Aim Stabilizer Sync by Gigabyte, which permit simultaneous backlight strobing and VRR (FreeSync or G-SYNC Compatible) performance, ULMB and G-SYNC cannot be active at the same time.

The new NVIDIA Reflex Analyzer program, which enables you to gauge the latency between the supported display and an appropriate mouse, is also included with a number of new G-SYNC monitors.

Monitors that work with NVIDIA Reflex Analyzer:

• Acer Predator X34S
• Acer Predator XB273U NX
• AOG AGON PRO AG274QG
• ASUS ROG Swift PG279QM
• ASUS ROG Swift PG259QNR
• AOC AGON PRO AG254FG
• MSI Oculux NXG253R
• Acer Predator X25
• Dell Alienware AW2521H

Mice that work with the NVIDIA Reflex Analyzer:

Last but not least, remember that NVIDIA Reflex Analyzer and NVIDIA Reflex are two distinct products.

In supported games, NVIDIA Reflex doesn’t evaluate input lag; instead, it lowers it.

You must have a graphics card from the NVIDIA GTX 900-series or later to use it, and the Reflex option must be enabled in a compatible game’s settings, such as:

• Fortnite
• Valorant
• Apex Legends
• Call of Duty: Black Ops Cold War
• Call of Duty: Modern Warfare
• Call of Duty: Warzone
• Destiny 2

List of G-SYNC Compatible FreeSync Monitors

It should be noted that the above-mentioned displays will function flawlessly with suitable NVIDIA cards, free from flickering, excessive ghosting, and other visual aberrations.

Other FreeSync monitors might support VRR with NVIDIA GPUs as well, but the performance quality isn’t assured in this situation. They might perform equally well, not at all, or have some problems.