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 manipulates 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.”



239 Comments For “G-SYNC 101”

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pegnose
Member
pegnose

@jorimt: Thanks a lot for this great article, I learned so much here!

I know I am a little late to the party, but I would like to ask something. I find it a little sad that G-Sync just as V-Sync allows for excessive frames to stack up. I have a powerful GPU and so I am (luckily) very often at the top limit of my monitor’s G-Sync range. I feel that I should disable V-Sync with G-Sync and accept some minor tearing for getting the best performance, particularly as I have an IPS display which I love color-wise but which already is far more laggy than my previous 1 ms G-Sync display (TN panel). I would rather not accept the 1 additional frame added by RTSS.

Here comes the question: does the NVCP option “Max. pre-rendered frames” not work? Or not all of the time with all of the games? Should it not do exactly what we all want: disable frame stacking and remove the need for a frame limit? I can’t find this setting being mentioned in your article at all.

I would also like to know whether the respective option in Overwatch does work well. If yes, does it not solve this issue at least for this game? You also stated that this option was ON for all your tests. If it works, you couldn’t have observed frame stacking with Overwatch, right?

And finally I would like to ask whether the 1 frame lag introduced by RTSS only applies when near the set threshold, or whether the limiter is active all of the time and the lag also occurs if operating far below the limit.

Thanks for you time!

EDIT: Out of curiosity, excessive frames stacking up would be limited by VRAM size, right?

antori
Member
antori

I had some crazy ripples and tearing while playing Worf of Warcraft with G Sync On. What fixed it for me was setting the frame rate 5 fps lower than my monitor refresh rate.
So if my monitor was set to 100 hz.
In game I had to set the maximum fps to 95. If it was at 100 i had tearing. Is this normal then ?

Koji_Online
Member
Koji_Online

Great write up thx!
The only thing I need clarification on is setting FPS cap to optimum 3 below monitor refresh; I get the reasoning, but I don’t think your article states if that was due to RTSS lag being further away from the game engine, and if setting in game would eliminate the need to go below the monitor refresh.

Like for example, I know people say you can set FPS caps in config files, but the native in game menu for Overwatch has the limiters only at common monitor refresh rates (60, 120, 144), and doesn’t give the option to specify a few frames below, without having to open a config file.

Would the in-game limiter work fine with these settings, wothout having to modify config or use an external limiter like RTSS?
As in, would these settings suffer from Vsync level delay (Gsync + NVCP Vsync both on), because they are set right at refresh rate thresholds?

Tappersweden
Member
Tappersweden

Hi. This guide and testing is great but i have one question. I have a 240Hz g sync monitor and i have it setup acording to your recomendation, the question is, do i ever have to limit my fps if a game dont even get close to 240 fps? I mean like 160-200 fps. If so , where do i sett the limit?

aScrubTurkey
Member
aScrubTurkey

pls help. i have a 1060 gtx and an acer predator and i can’t seem to setup g sync. my process stops at the start. i’m not given the option to set up g sync. i have the latest drivers. any help appreciated

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