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.



1462 Comments For “G-SYNC 101”

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BlackStorm82
Member
BlackStorm82

240Hz / GSYNC ON / 60FPS
240HZ / GSYNC OFF / 60FPS

Which is better in response time? Which one is better for blur?
G-Sync’s variable refresh rate function Does the screen response speed also affect it?

swaz
Member
swaz

Hi,
NVIDIA recently introduced a new “Max Frame Rate” setting in its Control Panel.
So I’m wondering if that uses the same FPS limiter tested via “Nvidia Inspector” on page 11.
If that’s not the case, when an in-game framerate limiter isn’t available, should I use RTSS or this new setting?
Thanks in advance.

DrGoku4star
Member
DrGoku4star

I’ve noticed more and more game now are ditching “Fullscreen exclusive” mode now such as Wow (World of warcraft) and Cod (Call of Duty) cold war and Rust.

One way i verify this is buy moving the volume scroll on my keyboard, and if i see the windows volume overlay appear in game, it’s not full screen exclusive?

Anyway, my main question is, with what i just said in mind, isn’t it better to leave The “Full screen optimizations” box ticked now? So that the DWM bypasses triple buffed v-sync?

Talos-LXIX
Member
Talos-LXIX

Hello there!
First i just want to say thank you so much for all the amazing work you guys do. in-depth analysis and guides like this are really helpful.

I just have a few things that I’m not entirely sure about.

1) You’ve found that G-SYNC completely bypasses the 1 frame of delay add by DWM in windowed/borderless. is that only the case if you’re within the G-SYNC range with V-SYNC enabled? could you still bypass it if you ran G-SYNC with V-SYNC off while being over your monitors refresh rate?

2) is G-SYNC+ V-SYNC off with fps over the monitors refresh rate identical to G-SYNC off + V-SYNC off?
For some reason some games (Apex Legends for example) lock their fps to my monitors refresh rate (120) when i try to disable G-SYNC via the per program settings on the NVCP.
I typically like to disable it for competitive FPS games as i can get much higher FPS than 120.

Hiram
Member
Hiram

Hello, I have read a lot, but I have a question.
In my case I play Fortnite, and if I limit the fps to 144 in the game and in the NVCP the screen tearing is not very noticeable, but it happens, otherwise if I play at limited 120 fps the screen tearing is much more noticeable, ( also putting 120hz in the NVCP).
Of course, my fps are not very stable when I get into a fight, they drop from 120 to 100 or a little less.
My question is, do I have to have V-sync activated?
I hope you can answer me

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