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.”



3068 Comments For “G-SYNC 101”

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gr1nv1ch
Member
gr1nv1ch

Hello
I have a g-sync compatible (free sync) monitor and use the settings specified in this manual. judging by the nvidia website, this monitor is an officially supported g-sync compatible monitor
I ran into the problem of the so-called “backlight flickering” at the moments of loading screens or too abrupt changes in the frame rate within the work of g-sync
The function itself works perfectly, however, there is very little information on this phenomenon on the Internet, and the one that is available also does not have enough data for analysis.
have you heard anything about this issue in a broader sense? what can cause it? without using vrr, the monitor works stably and does not flicker, which does not raise suspicions of its inoperability. maybe a software problem?

roro13200
Member
roro13200

Hello
I think we have asked you the question many times

Can you explain to me in a very simple way what difference there is between gsyn + vsync off and gsync off + vsync off.

because when I play with gsync on and vsync off I don’t have any screen tearing, yet I can see that gsync is working because there is the gsync indication at the top of my screen

thank you very much!

mujik104
Member
mujik104

Hello, yorimt. Thank you very much for the work done.
Sorry for my English. I would like to clarify one point. I have a Samsung Odyssey C27G75TQSI 240 Hz monitor. And if I put G-SYNC on + V-SYNC on + LLM on “Ultra”, then my fps in games is limited to 224. Is it right if instead of LLM on “Ultra” I will limit fps in RTSS or in-game (if available) at 237 fps and not at 224? Or will it be right to limit the fps exactly to 224 on my Samsung Odyssey C27G75TQSI monitor?

InBetweenNames
Member
InBetweenNames

Hey jorimt,

Just wanted to say that I re-tested a few of your hypotheses here at the end of 2021 and I wanted to confirm that all of your advice in this guide is still current and still accurately reflects how G-Sync should best be used. I also have a (potentially new) finding to report in regards to Vulkan’s vsync behaviour, at least as it exists in practice.

Vulkan games tend to use the FIFO Relaxed presentation mode when “V-sync” is enabled in game, because Vulkan itself doesn’t really have a native “v-sync” option like OpenGL and Direct3D 11 did. Instead, the v-sync is a part of the presentation mode itself. FIFO Relaxed, crucially *can* tear under certain circumstances (presentation rate lower than refresh rate of the display). What this means is if you enable vsync “in game” and not in the control panel, you could inadvertently get this presentation mode which is probably not what you want! However, if you enable vsync in the control panel, it will override the presentation mode to FIFO (not FIFO Relaxed), which is
the closest thing to traditional vsync in Vulkan and will not tear under any circumstances.

Another thing I wanted to point out is that, at least in my tests, setting vsync to Fast in the Nvidia control panel does not force the MAILBOX presentation mode in Vulkan as I would have expected — indeed, it does still seem to permit tearing when the presentation rate is slower than the display refresh rate. Also, it seems to incur higher latency regardless (which you have noted).

So, TL;DR is people interested in tear-free smooth experiences should still follow this guide.

I’m not sure if I can post links in here or not without getting flagged as a bot, but I encourage interested readers to check out the various Vulkan presentation modes for more information.

Thanks for all your hard work jorimt!

DZF
Member
DZF

is there any downside to using the -3 fps limit even if you’re not hitting the max refresh rate of your monitor?

For example, my monitor is 165hz which means my cap should be at 162 fps but let’s say that in certain games I’m only getting 120fps maximum. Will the 162 fps cap cause any ill effects such as giving me unecessary input lag or is it perfectly safe to just have the 162 fps cap on at all times as a sort of set-it-and-forget-it setting?

Sorry if this was a dumb question or if this was answered somewhere else and thank you for the guidance.

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