This is how Adaptive Sync Reduces Screen Tearing and Stuttering problems in Games

by Mayank
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Modern PC games feature realistic gameplay and amazing visuals. Modern GPU makers continually update their graphic cards to enable sophisticated technologies such as Ray tracing and DLSS in order to handle such graphically taxing games.

Aliasing effects in video games, which used to disrupt your flawless gameplay experience, have been fixed over the years thanks to continual GPU advancements and technologies like Anti-aliasing and anisotropic filtering.

However, there are a few issues that have been there for a long time but were just recently addressed by graphics card and display manufacturers. These issues are commonly referred to as: Screen tearing and stuttering.

We’ll get into the specifics of these problems later, but the essential thing to remember is that gaming displays and graphics cards have been able to solve the problem using a feature called Adaptive Sync. If you’ve ever read about or purchased a gaming display, you’ve probably come across this feature referred to as G-Sync (for Nvidia GPUs) or FreeSync (for AMD GPUs).

A brief description of screen tearing and stuttering in games is provided below.

Screen Tearing

Your graphics card delivers frames or images to your monitor at a variable rate. This is due to the fact that some gameplay events, such as a gunfight scene, necessitate more computation by the card, resulting in a drop in frame rate.

Other instances, such as basic player movements in the game, do not require as many calculations by the GPU, resulting in high frame rates.

Consider a scenario where you have a powerful GPU capable of pushing 120 frames per second in normal scenarios to a display but your monitor refresh rate is locked to 60 Hz (60 frames per second). What will happen to the game in this situation?

Screen Tearing issue visible in Battlefield 4
Credits: ViolentRumble

The issue is screen tearing, which basically means that your monitor will display parts of the first and next frame at the same time because it cannot keep up with the fast changing frames produced by the graphics card. Screen tearing is unpleasant and detracts you from your gaming experience.

How Nvidia’s V-Sync attempted to Resolve the Screen Tearing issue

Nvidia, the most popular graphics card maker, tried and, for the most part, succeeded in resolving the screen tearing issue.

When you enable V-Sync in games, it simply tries to match your GPU’s frame rates to the refresh rate of your monitor.

For example, if you have a 144 Hz display with V-Sync enabled in your game, the frame rates pushed by the GPU will not exceed 144 Hz, eliminating screen tearing problems.

Great! The problem has been resolved. Correct?

Actually, No. This is where the stuttering issue comes to life, ruining your gameplay experience once more.

Stuttering Problems due to V-Sync

When your graphics card can push more fps than your monitor can display, V-Sync is a wonderful option. However, as previously said, certain circumstances, such as explosions in games, take time for your graphics card to properly render.

In such cases, V-Sync will attempt to match the frame rates of your GPU and your display, but because the graphics card will not be able to push the next frame quickly enough, the previous frame will be shown on the monitor while the GPU renders the next frame.

A Graph showing stuttering issues with V-Sync when frame rates drop
Credits: Nvidia

It will seem as though the game is lagging visually. In gaming, this phenomenon is known as stuttering. If you experience this, it’s also one of the difficulties that will make you glance at your wallet and wonder why you spent so much money on your graphics card.

Adaptive Sync for the Save!

VESA was the first to standardise adaptive sync technology, which employed the Display Port standard. This enables the display’s refresh rate to adjust dynamically in response to the game’s frame rates. This significantly reduces stuttering and screen tearing.

Adaptive Sync may be thought of as a better form of V-Sync, in which V-Sync is enabled when the GPU pushes frames faster than the monitor’s refresh rate. V-Sync will be switched off automatically if the GPU is unable to push the appropriate number of frames to avoid stuttering.

Figure 1: When V-Sync is turned on and the frames pushed by the GPU drop below the display’s refresh rate, it causes stuttering in games
Figure 2: Adaptive Sync automatically turns off V-Sync when the frame rates drop to avoid stuttering issues in games

The diagrams above illustrate how Adaptive Sync contributes to a lag-free and smooth gaming experience.

The first diagram depicts what happens when the GPU takes more time rendering Frame B and V-Sync is enabled. As you can see, the Frame A is displayed twice on the screen to give the GPU time to render the Frame B. This is what causes Stutter or Lag in games.

The second figure describes what happens when Adaptive Sync is implemented. As you can see, if the GPU takes a while to render Frame B, the monitor will not display Frame A again, as it did in the previous example, but will instead wait for Frame B to fully render and then display Frame B and the following set of frames. Using Adaptive Sync reduces stuttering at lower frame rates.

Over a specific range, modern gaming displays enable adaptive refresh rates. The Asus MG278Q monitor, for example, can render frame rates ranging from 40Hz to 144Hz (Hz means frames per second).

G-Sync and FreeSync: What’s the Difference?

The two major GPU manufacturers, Nvidia and AMD, deployed adaptive refresh rate technology in distinct ways.

Nvidia employs G-Sync on it’s GPUs, a proprietary variant of adaptive refresh rate technology that needs extra hardware on G-Sync compatible monitors.

As a result, display makers like Asus and Samsung must pass a certification and pay a royalty to Nvidia in order for their displays to be G-Sync compatible.

With FreeSync, AMD adopted a more straightforward method. This technique is built on top of the VESA-standard Adaptive Sync, which means AMD doesn’t require display makers to pass a lengthy display certification process and doesn’t require any additional hardware on the displays.

As a result, displays that enable FreeSync are less expensive and more widely available. Hence, FreeSync-enabled gaming monitors are available in all price ranges.

I hope that this post has cleared up any confusion you may have concerning adaptive refresh rate or adaptive sync technology. So, the next time you go to the store to buy a GPU or a monitor, make sure that the GPU and display you’re buying are both compatible with the same adaptive technology: G-Sync or FreeSync.

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