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.”



3062 Comments For “G-SYNC 101”

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depatere
Member
depatere

First of all, thank you so much for this guide. This has been a lifesaver for me since getting my PG278Q a while ago.

I do have a question if you don’t mind. I recently upgraded my system to 5950X, 32gb 3600 CL16 RAM paired with a 2080 RTX and followed the guide in setting the best options for low latency G-Sync gaming.

My V-sync is on, I use ULLM on “Ultra”, “Performance mode” and use the Nvidia framelimiter for games that do not support ULLM to “141fps”.
However, with this capable system, I would assume I’d get the smoothest experience there is!

This unfortunately is not true. While in Rainbow Six Siege, I could be going around in circle with my mouse while moving, and you can see/feel some micro frame skips. Sometimes a bit longer. If I’d check my FPS counter, this goes from 138 FPS to maybe 136 or 120 or in some situations not lower than 138, but still I have the feeling it skips some frames, resulting in less smooth experience.

In DOOM after reloading a checkpoint, it takes a while to go to my refreshrate from 74 FPS during loading and then shooting upwards to 138 FPS again.

Is this caused by enabling G-Sync? Should I put ULLM to “On” instead of Ultra to avoid this?
Is this what frametime skips are called?

Hopefully, you’ll have the time to help me out, I’d certainly would donate as you guys are doing great work!

WonderGoliath
Member
WonderGoliath

Hi, when i’m playing certain games on a gsync 144hz monitor, i usually cap the frame rate for a more smoother experience. For instances, 60 fps capped on demanding games since my gpu couldn’t keep up. However, i noticed there’s framerate dip periodically (e.g. 60 to 57 etc). Only occur on 60 fps capped but not let’s say maybe higher? Like 70 or even 80 for some reason. What cause?

Scuggan
Member
Scuggan

Hey I’ve just add a second monitor (non gsync 60 Hz) and was wondering about global vsync. Will global vsync cause any problems with a dual monitor setup?
I know windows doesn’t handle dual monitor setups very well anyway but would it be better setting vsync on for each individual game and not global?

BlackStorm82
Member
BlackStorm82

Hello.

GSYNC ON 240Hz / LLM ON
GPU 50% FPS 150FPS

NO GSYNC 240Hz / LLM ULTRA
GPU 50% FPS 150FPS

In both situations, which is the lower inputlag?

hramulka
Member
hramulka

Good day! I am tormented by this question: Should I disable HPET in the BIOS??? Will HPET somehow affect the operation of G-Sync or the entire system as a whole if HPET is disabled in the BIOS? In my case, Ryzen 5 2600 and RTX 2070. Thank you in advance!

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