G-SYNC 101: Control Panel


G-SYNC Module

The G-SYNC module is a small chip that replaces the display’s standard internal scaler, and contains enough onboard memory to hold and process a single frame at a time.

The module exploits the vertical blanking interval (the span between the previous and next frame scan) to manipulate the display’s internal timings; performing G2G (gray to gray) overdrive calculations to prevent ghosting, and synchronizing the display’s refresh rate to the GPU’s render rate to eliminate tearing, along with the delayed frame delivery and adjoining stutter caused by traditional syncing methods.

G-SYNC Demo

The below Blur Busters Test UFO motion test pattern uses motion interpolation techniques to simulate the seamless framerate transitions G-SYNC provides within the refresh rate, when directly compared to standalone V-SYNC.

G-SYNC Activation

“Enable for full screen mode” (exclusive fullscreen functionality only) will automatically engage when a supported display is connected to the GPU. If G-SYNC behavior is suspect or non-functioning, untick the “Enable G-SYNC, G-SYNC Compatible” box, apply, re-tick, and apply.

Blur Buster's G-SYNC 101: Control Panel

G-SYNC Windowed Mode

“Enable for windowed and full screen mode” allows G-SYNC support for windowed and borderless windowed mode. This option was introduced in a 2015 driver update, and by manipulating the DWM (Desktop Windows Manager) framebuffer, enables G-SYNC’s VRR (variable refresh rate) to synchronize to the focused window’s render rate; unfocused windows remain at the desktop’s fixed refresh rate until focused on.

G-SYNC only functions on one window at a time, and thus any unfocused window that contains moving content will appear to stutter or slow down, a reason why a variety of non-gaming applications (popular web browsers among them) include predefined Nvidia profiles that disable G-SYNC support.

Note: this setting may require a game or system restart after application; the “G-SYNC Indicator” (Nvidia Control Panel > Display > G-SYNC Indicator) can be enabled to verify it is working as intended.

G-SYNC Preferred Refresh Rate

“Highest available” automatically engages when G-SYNC is enabled, and overrides the in-game refresh rate selector (if present), defaulting to the highest supported refresh rate of the display. This is useful for games that don’t include a selector, and ensures the display’s native refresh rate is utilized.

“Application-controlled” adheres to the desktop’s current refresh rate, or defers control to games that contain a refresh rate selector.

Note: this setting only applies to games being run in exclusive fullscreen mode. For games being run in borderless or windowed mode, the desktop dictates the refresh rate.

G-SYNC & V-SYNC

G-SYNC (GPU Synchronization) works on the same principle as double buffer V-SYNC; buffer A begins to render frame A, and upon completion, scans it to the display. Meanwhile, as buffer A finishes scanning its first frame, buffer B begins to render frame B, and upon completion, scans it to the display, repeat.

The primary difference between G-SYNC and V-SYNC is the method in which rendered frames are synchronized. With V-SYNC, the GPU’s render rate is synchronized to the fixed refresh rate of the display. With G-SYNC, the display’s VRR (variable refresh rate) is synchronized to the GPU’s render rate.

Upon its release, G-SYNC’s ability to fall back on fixed refresh rate V-SYNC behavior when exceeding the maximum refresh rate of the display was built-in and non-optional. A 2015 driver update later exposed the option.

This update led to recurring confusion, creating a misconception that G-SYNC and V-SYNC are entirely separate options. However, with G-SYNC enabled, the “Vertical sync” option in the control panel no longer acts as V-SYNC, and actually dictates whether, one, the G-SYNC module compensates for frametime variances output by the system (which prevents tearing at all times. G-SYNC + V-SYNC “Off” disables this behavior; see G-SYNC 101: Range), and two, whether G-SYNC falls back on fixed refresh rate V-SYNC behavior; if V-SYNC is “On,” G-SYNC will revert to V-SYNC behavior above its range, if V-SYNC is “Off,” G-SYNC will disable above its range, and tearing will begin display wide.

Within its range, G-SYNC is the only syncing method active, no matter the V-SYNC “On” or “Off” setting.

Currently, when G-SYNC is enabled, the control panel’s “Vertical sync” entry is automatically engaged to “Use the 3D application setting,” which defers V-SYNC fallback behavior and frametime compensation control to the in-game V-SYNC option. This can be manually overridden by changing the “Vertical sync” entry in the control panel to “Off,” “On,” or “Fast.”



3696 Comments For “G-SYNC 101”

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BloodyNZ
Member
BloodyNZ

Hey jorimt, thanks for this amazing article and all the research put into it.
My question is if everything present here still applies nowadays with all the new technology and it’s evolution, or anything changed.
I’m rocking a 5060ti but still on a 1080p 144hz display, so I’m trying to optimize it. I play a different range of games, from competitive to single-player. I just want a stable and consistent experience everywhere.

Treeplex
Member
Treeplex

Hello Dear jorimt! I am interested in one question, I will be grateful for the answer. In the game Fall Guys without vertical synchronization limit FPS 300, but with synchronization enabled FPS is equal to 360, what to do in this case?

KasaiRyujin
Member
KasaiRyujin

Hello jorimt, thanks for all the info.

I read almost all the pages of this post, but I’m still not sure what to set in my case.

I have a RTX 4090 + R7 7800X3D. I play on 1440p ~180Hz, so most games run at refresh rate. But I see that the frametime is unstable in some games.

I enabled G-SYNC and set V-Sync to “On”. Also set max framerate to 175 on NVIDIA App.

What should I do with Reflex and Low Latency Mode when I’m hitting refresh rate constantly?
I realized V-Sync has an option called “Fast”, should I use it?

Thanks in advance.

mike-lesnik
Member

Hello jorimt!
For what purpose did Nvidia choose such a significant frame limit for Reflex and LLM Ultra (for example 224 for 240Hz), if you prove that 2-3 frames are enough?

rundown
Member
rundown

Great series, thank you!

Sorry for yet another question about v-sync! 🙂 I do believe that screen tearing occurs with VRR on and v-sync off, but I’m trying to understand on a technical level how it happens with an FPS cap under the max refresh rate? Suppose a 144hz refresh and 140 fps cap.

My understanding is, the display waits in vertical blank until the new frame arrives and immediately scans it out in 1/144 seconds. If the frame limiter is doing its job, a new one shouldn’t arrive until 1/140 seconds after the first one, so the display should be in vblank again.

What am I missing — imperfections in the frame limiter?

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