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.”



3051 Comments For “G-SYNC 101”

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Zitteraal
Member
Zitteraal

Great article! After reading it through I tried your optimal settings and they are very optimal indeed! I have an LG OLED B9 and at 1440p (120hz) limit my framerate to 117 with Gsync+Vsync on.

If I wanted to record 60fps videos, though, I believe it’d be preferable to set it to 120fps to avoid stuttering due to frame division inconsistencies in the output video? In this case, would the best choice be to simply set the framerate limit to 120 (and keep Gsync+Vsync on) and accept the added latency?

If I were to go 4k (60hz) the latency would be too high for this solution, I think. Assuming my card sustains high enough fps, would Fast V-Sync be an option? FPS counters show the excess frames but I believe it should only be displaying(/capturing) at the refresh rate?

And I see that if I play a game that can only run in 30 or 60 fps using 1440p (120hz) mode with Gsync+Vsync on that the latency should be more than agreeable. I guess if I had a 144hz monitor I’d be able to do 120fps just as easily, too.

Mostly, I’m wondering if chasing 30/60/120fps for videos is workable in the Gsync landscape and if it simply means I must accept more latency.

Gottenmerkat
Member
Gottenmerkat

Hello, I’ve been using G-sync with your settings for the last 6 or so months and it’s been working pretty good besides the occasional stutter i seem to get when my framerate drops the slightest bit. Was wondering if it could be related to my Preferred refresh rate been set to ” Highest avaliable ” In Nvidia control panel. I use a monitor that can be overclocked to 165hz but i still have it on 144hz. Would that effect it at all?

olui
Member
olui

I’m pretty sure the Display Scan Diagram on the 6th page is wrong.
Given both frame ones start at 0s, at a rate of 142fps, the display would need to display it for 7.04ms.
Therefore, with VSync off, frame 1 would be displayed for the entirety of the 1st scan (6.94ms), and then the first 0.1ms of scan 2 (top rows of pixels).
With VRR on, scan 2 is delayed with increased VBI, and syncs correctly with the delivery of frame 2.
This diagram would be correct for frames higher than the refresh rate, in which the frames have to be displayed for less time than the max scan out time, so part of the newest frame would be inserted in the last milliseconds of scan (bottom rows of pixels). e.g. 150fps @ 144hz.

olui
Member
olui

I can see why the designer got confused, as the time stamps are in fractions of 1/144. So he marked the end of frame 1 at 0.74/144 thinking it was 7.04ms. But ending 1st frame at 0.74/144 would result in a frame rate of 194, not 142 :p

mig23zcyther
Member
mig23zcyther

I am new here bro and I am hoping you guys can help me. 🙂 I am wondering if this setup would be an issue. My monitor’s native refresh rate is 240 hertz with a G-sync compatible and NVCP v-sync on and in game v-sync is off. I am currently using RTSS to limit my framerate to 162 fps since I think this is the optimal output and most attainable frames in for most games that I play. Would this setup cause any additional latency or issues compared if I set the fps limit 3 frames less(237 or 236 fps limit) instead? Thanks in advance!

fanatycme
Member
fanatycme

what if game has no v-sync built in? i read that i need v-sync for g-sync to work properly, so if i enable vsync inside nvcp, along with gsync fullscreen, and fps cap -3 fps i am good?

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