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.



1948 Comments For “G-SYNC 101”

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Evok99
Member
Evok99

I just purchased the new Viewsonic XG2431 that features the blurbusters 2.0 approval. I plan on setting up the PureXP+ tomorrow to play with Overwatch. I can max Overwatch out at about 340fps consistently. Do you have any recommendations in how to setup gsync and PureXP+ for the lowest framerate? Should i cap my frames to 237fps with gsync and vsync enable even though I can get a much higher frame rate?

Maybe I would be better off with a 360hz monitor and no light striving? Thank you. This is all new to me.

roro13200
Member
roro13200

hello I wanted to know in nvcp, the refresh rate we must put it on which option? app-controlled or higher? I have an asus and there is a trace free option that adds input lag?
thank you for your work!

blz
Member
blz

Hello,
I play at 250-290 fps on valorant/csgo, 190 fps on valorant on a MSI G24C monitor should I use freesync (gsync compatible) when my frame rate is way above my 144hz refreshrate? Will the added input lag be worth the lesser tearing?

reaxtic
Member
reaxtic

Hi,
best settings for low input lag is a Gsync + LLM + V-sync in NVCP?

rocky.gaoa
Member
rocky.gaoa

hi,you said
“In-game Settings:
Disable all available “Vertical Sync,” “V-SYNC,” “Double Buffer,” and “Triple Buffer” options.”

does it mean prohibit the V-Sync working finally?

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