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.



2611 Comments For “G-SYNC 101”

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Alex UA6
Member
Alex UA6

Hey brother, sorry to bother you again but I’m confused about one thing so in the game I play insurgency sandstorm it does not support freesync or Gsync. So in game I have limited my frames to my monitors, refresh rate, and enabled Vsync so I don’t get screen tearing. If I disable Vsync it’s unbearable. If in a newer game like modern warfare 2 would I want Vsync disabled? Also, if there’s anything you can tell me about the set up for insurgency, please feel free to let me know.

tbowly
Member
tbowly

is this normal? i have 60 stable fps on my 165hz Gsync monitor but the refresh rate keeps changing and is not stable, it keeps changing constantly to 50-80Hz happens to all of my games, and when a game has like 80 fps it keeps changing to 60-100Hz

tbowly
Member
tbowly

here’s the video of my problem: https://streamable.com/mm3oun

mustardpapi
Member
mustardpapi

I have a XL2546 so it is not G sync compatible. Should I still utilize 236 fps while using DYAC + nvidia V sync? Or are these settings G sync specific?

Alex UA6
Member
Alex UA6

Hey brother, my buddy, just picked up an LG ultra gear 165hz monitor with adaptive sync. I’m a little confused with the word adaptive sync. Is it just another word for free sync or G sync? I’m trying to understand if I should enable V sync when using adaptive sync. On my free sync display I enable V sync to eliminate screen tearing.

BNThuan
Member
BNThuan

Hi. Im playing ” crossfire” with monitor 165 hz . I setted up G sync “on” +V sync “on”+ limited fps “162” but in game fps still from 199-200 and lag. I have already changed setting NVCP but that problem has not improved. please give me advice. thanks

Karambol2K
Member
Karambol2K

Where did you cap fps? In game or in nvidia panel? I personally recommend RTSS for capping frames.

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