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G-SYNC 101: Control Panel

Published Jun 20, 2017 by in: G-SYNC

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.”

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3070 Comments For “G-SYNC 101”

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nheira0000
Member
nheira0000

I have a question .
How should I install nvidia with the pubg game?
I have pg279q and strix 1070ti

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5 years 6 months ago
ynemis
Member
ynemis

First thanks for the amazing written article, it cleared up many questions I had. There are still some thing that I don’t fully understand.

As you made clear G-SYNC on + V-SYNC on + -3 FPS limit are the best settings for a tear free and low input lag solution. My question is about the RTSS fps limiter, if I use it in a game that runs at an average of 150 fps on a 165Hz G-SYNC monitor it makes sense to use the RTSS fps limiter because the framerate may spike up to above the maximal refresh rate of 165Hz causing input lag. Does the RTSS fps limiter also cause the additional 1/2 frame delay if the framerate stays below the 162 fps limit?

My second question is about the difference in input lag between G-SYNC on+ V-SYNC off + FPS uncapped vs. G-SYNC off + V-SYNC off + FPS uncapped. I want to play CSGO at the lowest input lag possible and I don’t mind tearing there. Does having G-SYNC enabled without V-SYNC, but playing above the max refreshrate add some additional input lag compared to turning G-SYNC off? I want to know if I should bother turning G-SYNC off every time I play competitive. Thanks a ton in advance!

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5 years 6 months ago
jorimt
Author
jorimt

The RTSS FPS limiting function (and added lag; which is laggier than an in-game cap, but NOT laggier than uncapped at the same FPS, mind you) is only active when the framerate hits the set limit.

For those two scenarios within the G-SYNC range, the difference is 0% tearing vs. possible tearing. Above the G-SYNC range/max refresh rate, G-SYNC on + V-SYNC off + uncapped FPS equals G-SYNC off + V-SYNC off + uncapped FPS until the FPS goes below the refresh rate, so yes, you’re safe to leave G-SYNC enabled in that scenario; above the refresh rate, it’s the same thing as plain old, standalone V-SYNC off.

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5 years 6 months ago
ynemis
Member
ynemis

Thanks for the reply! So in that case having RTSS FPS limiting function on in every game even if well below the max refresh rate (provided there is no in-game fps limiter) is better than no RTSS FPS limit, because RTSS doesn’t add extra lag when it doesn’t activate?

Would you mind explaining why the added lag isn’t higher with RTSS compared to uncapped at the same FPS, if it’s within the G-SYNC range of course?

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5 years 6 months ago
jorimt
Author
jorimt

Yes. The RTSS limiter is only active when the FPS is at/above the set limit.

As for the answer to the second question, that’s much more involved, but to grossly simplify, when the FPS is sustained above the RTSS limit, it’s effectively like having pre-rendered frames at zero.

Uncapped at the same FPS can’t do that, since there is no guaranteed frametime, so pre-rendered frames remain in effect (same thing happens whenever the FPS is below the RTSS limit).

For this reason, an RTSS limit can actually have lower input lag than uncapped at the same FPS, so long as the framerate is at or above the set RTSS limit.

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5 years 6 months ago
ThatBuild
Member
ThatBuild

What would have less input lag/better response on a 165 hz monitor with gsync enabled.

Capping at 144 fps with Vsync “off” or capping at 160 fps with Vsync “on”?

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5 years 7 months ago
jorimt
Author
jorimt

If you’re at 165Hz, you want a -3 FPS cap (162 FPS). The -3 FPS limit is relative to the refresh rate, so an 144 FPS limit doesn’t factor into a 165Hz scenario.

As for G-SYNC enabled + V-SYNC on vs. off, the difference in input lag at 165Hz between the two is virtually the same as it is at 144Hz; An extra 21 FPS/Hz barely makes an input lag difference worth noting.

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5 years 7 months ago
mayc
Member
mayc

One question and sorry for my bad English. My monitor is 120hz and most games do not give me 120fps stable, usually go above 60 (60-80-95-65-…) but there are many peaks. Although I don’t have tearing with the gsync, if I notice sometimes some stuttering with those peaks of fps dancing. I have done some test to force the monitor to 60hz and play at 60fps and I get the feeling that the sensation is more stable, even the scrolls feel softer. Is this technically possible and recommended in these cases or is it pure placebo?

thanks

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5 years 7 months ago
jorimt
Author
jorimt

Probably a placebo.

G-SYNC 60 FPS at 60Hz is basically normal, standalone V-SYNC.

The stutter you are experiencing with variable framerates at 120Hz is possibly frametime spikes, which happen at 60Hz too, they are just less noticeable at a locked 60 FPS because your system will have an easier time sustaining that framerate.

Dropping from 60 FPS to <30 FPS and back is less jarring than dropping from a higher framerate. E.g. The higher the average framerate + refresh rate, the more noticeable any form of stutter is.

Some games may have fixed internal frame pacing however, which means they only evenly deliver frames at 30/60/120 FPS multiples. In these cases, any framerate between these values duplicate frames, causing the appearance of stutter.

It's very rare, but for those sort of games, you can try setting your monitor to 120Hz and limiting the framerate to 60 FPS.

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5 years 7 months ago
DjMeleeForm
Member
DjMeleeForm

I have a question about the G-Sync range. I have a 240Hz monitor and have been using the optimal settings stated by this site (G-Sync + V-Sync On (Nvidia control panel), 237 FPS limit), but in certain games there is only a preset number of FPS limiting options (60, 120 and 144hz for example). Is a framerate of 144fps still within the G-Sync range of a 240Hz Monitor or am I forced to use a framerate limiter to get the sweet spot of G-sync with (almost) no additional input latency and no tearing?

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5 years 7 months ago
jorimt
Author
jorimt

144 FPS is well within the G-SYNC range at 240Hz. You don’t need to do anything else in that scenario but have G-SYNC + V-SYNC on.

Same goes for 60 FPS @240Hz and 120 FPS @240Hz.

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5 years 7 months ago
wpDiscuz

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