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.



842 Comments For “G-SYNC 101”

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BlurBustersFans
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BlurBustersFans

i’m trying to setup G-Sync properly according to the optimal setting in this guide. In the game Call of Duty Warzone setting under custom FrameRate Limit I’ve set it to 138FPS because i have a 144hz gsync compatible monitor , next to this setting it has a text that says “Note that if Vsync is ON, your maximun framerate is still going to be your monitor’s refresh rate” . i turned on vsync in NVCP which this guide suggest. vsync Disabled in game setting. Does that mean the game engine will still limit my fps to 144 instead of 138? if so that is no good for gsync right ? because i want my fps to be a few fps below my monitor refresh rate
if i understand correctly. is there a way to verify if the game’s framerate limiter is capping my fps at 144 or 138 ? i have turned on the game’s fps counter , i see the counter fps number sometimes goes above 138. in between 140-142 and ocassiacionly reach 144 for like half a second and go back down. therefore i am not sure the in game fps limiter is working as intended. is the counter 100% accurate ? should i use NVCP’s frame cap instead? but that usually add more latency than in game’s setting and i dont want more latency. Any suggestions?

UPDATE: after some testing with the in game frame limit setting. it turns out the cap is working , i set the limit to 80 fps and the game indeed stay at around 80 fps reading from the in game fps counter, so it is not capping my fps at my monitor’s refresh rate with Vsync ON like the in-game description say , so i dont know why it says that. and i notice even tho i set it to 80 fps the fps counter fluctuated at around 78-83 just like when i set it to 189 it fluctuate between 136-143. so in this siutation do i trust the fps counter number? or should i set a number even lower than 138 so that i can guarantee the fps counter number would never go above my monitor’s refresh rate 144 to keep gysnc activated ?

nikoisconfused
Member
nikoisconfused

Hello! A week ago i bought a HP 24x G-SYNC compatible monitor , although im not fully sure if it works as intended. I am having issues with Dead By Daylight and the devs told me to lock the game at 60FPS , i did , and god its awful. I have tried everything , G-SYNC + VSYNC/G-SYNC ON + VSYNC OFF , nothing works and i have no idea why. On the Pendulum demo G-SYNC seems to be working perfectly , but sadly not in-game. Any ideas?

Zehdah
Member
Zehdah

I recently started playing older games, the main one being Elder Scrolls Oblivion at the moment and I play on a 144hz Gsync monitor. The game is locked to 60 FPS, going higher results in physics issues, so I am wondering if there are any particular settings I should be using in this situation for smooth gameplay. I’ve had people suggest turning Gsync off and Vsync on, which sounds like a strange thing to do to me, but I have no idea!

Mojoz
Member
Mojoz

Jorimt,

Thank you so much for this guide. It’s fantastic and you should be proud of how many people you’re helping here.

I just had a few questions I was hoping you could answer for me, to make sure I’m understanding this all correctly.

Notes: My monitor is an ASUS TUF Gaming VG259QM 240hz (overclockable to 280hz).

1. For competitive gaming, I should run G-Sync on and V-sync on (through Nvidia control panel) and cap my FPS 3 below my HZ. E.g. at 240hz I should cap at 237 FPS?

2. A follow-up question to this, what about capping FPS lower significantly lower than your HZ? Does it matter? For example, I’m currently playing Divinity Original Sin 2 and capping this at 120fps with 240hz (I rather have a stable FPS than have fluctuating 125-150fps). Is this okay or should I leave it uncapped?

3. Is more HZ better in every situation? My monitor is 240hz (overclockable to 270hz and 280hz). I was thinking of overclocking to 270hz (I’m not sure I want to run it at its limit). Does it matter if it’s not dividable by an even number (e.g. 270 and not 274 or 280). In your words, more Hz is better with g-sync right?

4. My monitor comes with something called “FreeSync” which can be used alongside G-Sync. I have no idea what this is. Should I just ignore it and leave it off?

Many, many thanks.

Mojoz

Nsnake771
Member
Nsnake771

Hi guys,
I recently played R6s Vulkan and as I do with every other games, I set on NVCP the max frame rate to 141, but it didn’t work in-game. Does the max frame rate featured doesn’t work on Vulkan games ?

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