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


Beyond the Limits of the Scanout

It’s already been established that single, tear-free frame delivery is limited by the scanout, and V-SYNC OFF can defeat it by allowing more than one frame scan per scanout. That said, how much of an input lag advantage can be had over G-SYNC, and how high must the framerate be sustained above the refresh rate to diminish tearing artifacts and justify the difference?

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

Quite high. Counting first on-screen reactions, V-SYNC OFF already has a slight input lag advantage (up to a 1/2 frame) over G-SYNC at the same framerate, especially the lower the refresh rate, but it actually takes a considerable increase in framerate above the given refresh rate to widen the gap to significant levels. And while the reductions may look significant in bar chart form, even with framerates in excess of 3x the refresh rate, and when measured at middle screen (crosshair-level) only, V-SYNC OFF actually has a limited advantage over G-SYNC in practice, and most of it is in areas that one could argue, for the average player, are comparatively useless when something such as a viewmodel’s wrist is updated 1-3ms faster with V-SYNC OFF.

This is where the refresh rate/sustained framerate ratio factors in:

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

As shown in the above diagrams, the true advantage comes when V-SYNC OFF can allow not just two, but multiple frame scans in a single scanout. Unlike syncing solutions, with V-SYNC OFF, the frametime is not paced to the scanout, and a frame will begin scanning in as soon as it’s rendered, regardless whether the previous frame scan is still in progress. At 144Hz with 1000 FPS, for instance, this means with a sustained frametime of 1ms, the display updates nearly 7 times in a single scanout.

In fact, at 240Hz, first on-screen reactions became so fast at 1000 FPS and 0 FPS, that the inherit delay in my mouse and display became the bottleneck for minimum measurements.

So, for competitive players, V-SYNC OFF still reigns supreme in the input lag realm, especially if sustained framerates can exceed the refresh rate by 5x or more. However, while at higher refresh rates, visible tearing artifacts are all but eliminated at these ratios, it can instead manifest as microstutter, and thus, even at its best, V-SYNC OFF still can’t match the consistency of G-SYNC frame delivery.



977 Comments For “G-SYNC 101”

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compddd
Member
compddd

My monitor is 144Hz but if I’m playing a game like Sekiro Shadows Die Twice which has a max FPS limit of 60 due to being a console port, do I set my FPS limiter to 57 FPS for that game in RTSS?

svatt
Member
svatt

Hi guys, i have bunch of problems with freesync.
My pc: r5 3600, rtx 2070, 144hz freesync monitor

My problem is that normally when i turn on gsync compatible in NVCP(i also turn on gsync indicator) its not working games are just stuttering and indicator is not showing, BUT when i go to any game properties and i disable thing called “disable fullscreen optimalisation” gsync compatible(“freesync”) starts working and indicator start showing but im noticing heavy flickering(i know its normal in loading screen but im noticing it like every 10sec. in game playing). okay so that is my first problem, second is why when i restart my computer and i have enabled gsync compatible but NOT DOING that thing in game properties(disabling fullscreen optimalisation) gsync compatible just starts working and again with high flickering.
Gsync compatible is just sometimes working and sometimes not after restarting pc. I go to the shop where i buy monitor and they replace monitor for the same model but problem is stil here. Is there any way to slove it or i must buy certified Gsync compatible monitor wich is in Nvidia list or is there problem in any hardware part like GPU or MB?

thanks for any help and sorry for my english but im from slovakia.

Jhaniel
Member
Jhaniel

So GSYNC ON, VSYNC ON. In game settings VSYNC OFF and cap fps to 141 if I have a 144hz monitor? Anything else TIA

DeepskyScorpion
Member
DeepskyScorpion

I would like to ask if the behaviour of VSYNC with GSYNC enabled on an Nvidia GPU — where the module deals with frame time variance better and doesn’t allow suddent changes in frame time to introduce tearing — applies to Freesync monitors, with GPU from both venders? Or do the GPU and/or the display treat it differently depending on the venders of both components?

stollywood
Member
stollywood

Hi there,

Great article!!

I have 8700k and 2080ti and when running at 1440p on high settings I’m having some stuttering So tried to run gysnc on, vsync on (nvc), llm on & and in game limiter 3fps under my 144hz refresh.

Problem is im hitting 100% gpu usage when i look in. Hw monitor when play destiny 2 and COD MW.

What is the best thing to do?

I have changed some options in nvidia control via some other guides and not sure if that is causing it.

Surely my gpu being 2080 ti sound run under 100% all all of the time. Temps are around 82oC max

Cheers Ryan

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