G-SYNC 101: G-SYNC Ceiling vs. V-SYNC


Identical or Fraternal?

As described in G-SYNC 101: Range, G-SYNC doesn’t actually become double buffer V-SYNC above its range (nor does V-SYNC take over), but instead, G-SYNC mimics V-SYNC behavior when it can no longer adjust the refresh rate to the framerate. So, when G-SYNC hits or exceeds its ceiling, how close is it to behaving like standalone V-SYNC?

Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings
Blur Buster's G-SYNC 101: Input Latency & Optimal Settings

Pretty close. However, the G-SYNC numbers do show a reduction, mainly in the minimum and averages across refresh rates. Why? It boils down to how G-SYNC and V-SYNC behavior differ whenever the framerate falls (even for a moment) below the maximum refresh rate. With double buffer V-SYNC, a fixed frame delivery window is missed and the framerate is locked to half the refresh rate by a repeated frame, maintaining extra latency, whereas G-SYNC adjusts the refresh rate to the framerate in the same instance, eliminating latency.

As for “triple buffer” V-SYNC, while the subject won’t be delved into here due to the fact that G-SYNC is based on a double buffer, the name actually encompasses two entirely separate methods; the first should be considered “alt” triple buffer V-SYNC, and is the method featured in the majority of modern games. Unlike double buffer V-SYNC, it prevents the lock to half the refresh rate when the framerate falls below it, but in turn, adds 1 frame of delay over double buffer V-SYNC when the framerate exceeds the refresh rate; if double buffer adds 2-6 frames of delay, for instance, this method would add 3-7 frames.

“True” triple buffer V-SYNC, like “alt,” prevents the lock to half the refresh rate, but unlike “alt,” can actually reduce V-SYNC latency when the framerate exceeds the refresh rate. This “true” method is rarely used, and its availability, in part, can depend on the game engine’s API (OpenGL, DirectX, etc).

A form of this “true” method is implemented by the DWM (Desktop Window Manager) for borderless and windowed mode, and by Fast Sync, both of which will be explained in more detail further on.

Suffice to say, even at its worst, G-SYNC beats V-SYNC.



1873 Comments For “G-SYNC 101”

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blaskovic
Member
blaskovic

Hi jorimt. I have a question for you. Sometime in older games (2011 – 2013) I have a drop frame from 144 to 140 or 144 to 135 and I notice this microstutter with G-sync but in other games if I have this drops (for example in Dirty Rally) I don’t see anything. My question is this: Why in some case (games) G-Sync seems works but in other circumstances (games) i see this microstutter? G-Sync shouldn’t avoid Microstutter? Thank you

stadiofriuli
Member
stadiofriuli

I’ve got a question. Got the Dell S2721DGF(A) which is G-Sync compatible, I’m running the monitor at 165Hz.

So what I basically did is to set a FPS cap @161 with RTSS.

Enabled G-Sync fullscreen in NVCP.

Enabled V-Sync in NVCP.

According to the guide V-Sync within the G-Sync range should still act like for native G-Sync monitors when it’s an official supported G-Sync compatible monitor.

What happens for me though is.

When V-Sync is enabled FPS cap at 158, not 161 as set in RTSS.

When I then disable V-Sync and have only G-Sync running it’s capped at 161 again.

So my question really is why this weird behaviour?

Should I activate or deactivate V-Sync in my case?

SvenL
Member
SvenL

Hi,
First of all, thank you so much for creating such an amazing guide. After reading through a few more questions arose.

I’m playing Warzone (FPS game) on a 1080p 144hz free sync monitor with an RTX 2080Ti graphics card. (I achieve 170-180 fps in game uncapped, which is above the refresh rate of my monitor)

My goal is to have a 100% tear-free gaming experience with the least amount of input lag to achieve the best possible accuracy.

First, I took over the following settings from you
NVCP: G-Sync & V-Sync: On

But when it comes to the FPS limiter, I’m still unsure which is best in my case. (Warzone also supports reflex)

In-Game FPS Limiter (141 FPS cap)
Reflex: On / On + Boost
RTSS / NVIDIA’s Max Frame Rate (141 FPS cap)

The question is which of these options has the lowest input lag and at the same time the most constant possible frame time. (I assume these 2 factors are especially important for FPS games)
Or what you think would be the best sweet spot out of all of these options.

With reflex activated (On + Boost), I noticed that the frame rate varies (around 138 fps). I’m not sure whether this will have a negative impact on my frame time or input delay, as I could easily achieve a constant 141 FPS with my graphics card. Should I then prefer the in-game FPS limiter or RTSS / NVIDIA’s Max Frame Rate over reflex?

Thank you very much

RoseGoldCrobat
Member
RoseGoldCrobat

I signed up here since you seem to know a lot about this. I have a very strange issue.

I have a monitor that is Gsync compatible and Gsync is on in fullscreen mode.

When I play certain games, the current ones I’ve seen it in are Red Dead Redemption 2 and Hitman 3 I would like to have gsync on and vsync on. The problem is when both settings are on at the same time my FPS caps to 72 fps, half of my monitor’s refresh rate. I don’t understand why this is happening. Could I be missing a setting?

Zehdah
Member
Zehdah

Hello. I have a new monitor, it’s a Samsung G7 Odyssey which is 1440p 240hz with Gsync. I’m wondering what you would recommend for optimal performance/gaming with that setup since it’s unlikely I will hit 240hz in a game at 1440p with a 1080ti, should I still follow the above instructions and cap to 237 along with vsync on in CP, off in game? Curious if there’s any extra things I need to do.

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