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.



1304 Comments For “G-SYNC 101”

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Zrex
Member
Zrex

Hi I just recently bought the new Asus PG259QN 360hz Monitor just wanted to get a little bit of information on what’s best for a competitive settings/setup.

– Should I use g-sync with the optimal settings or Fixed refresh uncapped ?

– Game I usually play is siege and its uses DX11 & vulkan api, should I run DX11 api with LLM on/ultra or vulkan with LLM off ?

Also is it fine to use display scaling or GPU Scaling in nvcp does it matter in g-sync fixed refresh rate settings ?

– I also use 2 monitors one is at 60hz can go to 144hz and one is my main at 360hz will that conflict with anything including stutters etc?

nevo2323
Member
nevo2323

Hi, I understand that gsync barely adds lag compare to only vsync and offer a tearless experience but how does it compare to the fixed refresh settings? which one gives the lowest input lag? (At frame rates lower than refresh rate and higher than it, each case to its own of course)
Thanks!

hramulka
Member
hramulka

Thank You so much for being there and helping users!!!

mct1980
Member
mct1980

Nice bit of info here. Cheers! Is it possible to avoid screen flickering when fps drops below 30 when the gpu usage is low? Like forcing it to run at minimum 30 fps even if the application doesn’t want it to?

BlackStorm82
Member
BlackStorm82

Hello, God of Knowledge.
G-SYNC ULTIMATE VS G-SYNC VS G-SYNC COMPATIBLE

Is G-SYNC ULTIMATE or G-SYNC more advantageous in Inputlag than G-Sync compatibility?

Can you say that the compatibility between G-Sync and G-Sync differs in the smoothness of the screen?

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