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.



2431 Comments For “G-SYNC 101”

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elexi
Member
elexi

Thanks for this Guide!
i already use gsync on + vsync on + 141 FPS LOCK on 144 hz screen.
some questions:
1) I often play VR games. Does Gsync + vsync combo somehow affect VR performance?
2) Is it combo good for Gsync-compatible screen, like mine LG UltraGear 27GL83A-B ?
3) And should i use LLM On or should i set in on AUTO (now i play with auto)? I mostly play non cybersport dx12/vulkan games
4) Does DSR DLDSR tech affect gsyncvsync combo and lag?

CorvusCorax
Member
CorvusCorax

I have read the entire guide. However, I have one question that is bothering me and I can’t find a reasonable answer anywhere. I have a monitor with a refresh rate of 240Hz, but I can’t use G-Sync. What happens if I set the frame limit to e.g. 100fps and turn on V-sync?

richardjohnsonfa
Member
richardjohnsonfa

If I have a amd gpu and freesync monitor, shall I follow your optimal settings but using freesync instead of g sync and amd chill fps limiter 3 fps under my monitors refresh rate instead of nvcp’s fps limiter. So it would essentially be freesync (using amd software) + v sync (using amd software or in game) + -3 fps below refresh rate limiter (using amd software, i.e. amd chill, or in game). Would it work the same as in your optimal settings? Thanks jorimt 🙂

Scandaal
Member
Scandaal

What do I need to set in the NVCP display settings if I use G Sync, I have an ASUS VG248QG 165HZ monitor.

At the moment I have No Scaling + Display set

Scandaal
Member
Scandaal

Hello I play WarZone 2 and I am interested in the G SYNC + V Sync setting, I currently have G Sync and V Sync enabled (In NVCP), also I enabled NVIDIA Reflex in the game settings and now my FPS is limited to 158fps (Monitor 165hz).

Can you tell me the optimal G Sync settings for this game, maybe there are better options to get optimal smoothness without frame tearing and micro staters

RTX 3060 / 12400 5Ghz / 3466 CL14

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