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.



1772 Comments For “G-SYNC 101”

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warface9991
Member
warface9991

Thanks for detailed article. This is unprecedented.
Yet, I have a question about low fps gaming. You have written that the cap should be ~3 fps below the maximum refresh rate but most AAA games cannot be run at 140fps at all. In this case, how should I cap my framerate on @120Hz or on @144hz etc. in order to have a smooth experience?
Thank you for everything.

Zehdah
Member
Zehdah

Hello. I’m wondering if there’s any negative to me using G-sync as explained above but in borderless windowed mode (enabling the option in NVCP too)? The only reason I want to do this is because I play a game (Final Fantasy XIV) which doesn’t work properly in full screen mode, but flawlessly in borderless windowed mode.

voicon
Member
voicon

G-Sync + No FPS Limit vs V-Sync + No FPS Limit, who is less input lag ?

voicon
Member
voicon

In Monitor 165 Hz, G-Sync + No FPS Limit vs G-Sync + ingame FPS 162 who is less input lag ?

Ku6epgeg
Member
Ku6epgeg

Do I need to set low latency mode on for Resident Evil Village?
I have an MSI GeForce RTX 3070 ventus 3X OC and a Samsung Odyssey C27G75TQSI monitor.
I enable G-sync and v-sync in Nvidia drivers.
I get 90-100 frames per second in Resident Evil Village, do I still need to enable low latency mode?
And also wanted to know another low latency mode for the World of tanks game?
Maybe I can just enable vertical sync and low latency mode in nvidia settings permanently?

xm3lite
Member
xm3lite

Hi, I wanted to ask, is V sync on in control panel still recommended over in-game v sync after MPO was added? thanks.

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