G-SYNC 101: G-SYNC vs. V-SYNC w/FPS Limit


So Close, Yet So Far Apart

On the subject of single, tear-free frame delivery, how does standalone double buffer V-SYNC compare to G-SYNC with the same framerate limit?

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

As the results show, but for 60Hz (remember, a “frame” of delay is relative to the refresh rate), the numbers are relatively close. So what’s so great about G-SYNC’s ability to adjust the refresh rate to the framerate, if the majority of added input latency with V-SYNC can be eliminated with a simple FPS limit? Well, as the title of this section hints, it’s not quite that cut and dry…

While it’s common knowledge that limiting the FPS below the refresh rate with V-SYNC prevents the over-queuing of frames, and thus majority of added input latency, it isn’t without its downsides.

Unlike G-SYNC, V-SYNC must attempt to time frame delivery to the fixed refresh rate of the display. If it misses a single one of these delivery windows below the maximum refresh rate, the current frame must repeat once until the next frame can be displayed, locking the framerate to half the refresh rate, causing stutter. If the framerate exceeds the maximum refresh rate, the display can’t keep up with frame output, as rendered frames over-queue in both buffers, and appearance of frames is delayed yet again, which is why an FPS limit is needed to prevent this in the first place.

When an FPS limit is set with V-SYNC, the times it can deliver frames per second is shrunk. If, for instance, the FPS limiter is set to 59 fps on a 60Hz display, instead of 60 frames being delivered per second, only 59 will be delivered, which means roughly every second a frame will repeat.

As the numbers show, while G-SYNC and V-SYNC averages are close over a period of frames, evident by the maximums, it eventually adds up, causing 1/2 to 1 frame of accumulative delay, as well as recurring stutter due to repeated frames. This is why it is recommended to set a V-SYNC FPS limit mere decimals below the refresh rate via external programs such as RTSS.

That said, an FPS limit is superior to no FPS limit with double buffer V-SYNC, so long as the framerate can be sustained above the refresh rate at all times. However, G-SYNC’s ability to adjust the refresh rate to the framerate eliminates this issue entirely, and, yet again, beats V-SYNC hands down.



2774 Comments For “G-SYNC 101”

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ULA
Member
ULA

Hi there!

First of all, thanks for the guide! helped a lot.

Now, to my question. I am looking to play Cyberpunk with the path-tracing settings, which is obviously a computional nightmare—even for my 4090. This would be the first time I will enable DLSS 3.0, which I will refer to as frame-generation (FG) from here on it. I will be using the perfomance-mode of DLSS 2.0, since I game at 4k and I want to mininze the input lag from FG; I believe the higher the native frame rate, the lower the input delay due to FG.

Now, from what I know, is that I should still enable V-sync from the NVIDIA control pannel. However, it is not needed to set the frame rate 3FPS below the monitor’s refersh rate, since that is automatically done by Reflex (which will be enabled by default when using FG).

However, I would still like to cap my frame rate below my native 120FPS, say at 100FPS, so that the frame rate is consistent. But, I noticed that the frame-rate limiter (both in-game and in the NVIDIA control panel) has zero affect. Is this beheviour expected?

Dogelol
Member
Dogelol

I used the Gsync on – Vsync on (in NVCP) and frame rate cap to 160 (165hz max) from RTSS however I experience varying degrees of flickering in menus mostly but in some games too.

From what I know there is no way to fix the flickering as it is something normal for VA/OLED’s.

My question is if I can not detect tearing (most likely there is some but either high fps/oled smoothness or simply my eyes not detecting it)

I am thinking about playing with Gsync off and no vsync on and just an fps cap. Would that impact my experience?

Ideally I would like to keep gsync on due to the smoothness I feel with it however the flickering is a deal breaker for me.

What is the best combination if I do not wish to use Gsync, should I keep vsync and fps cap, or only the fps cap?

Thank you!

august
Member
august

best settings for eafc 24?

rec0veryyy
Member
rec0veryyy

hi, i have been playing cs2 for several weeks, my monitor is 1440p 144hz with gsync compatible, in the nvcp i have gsync on + vsync on, i also limit the fps to 141 inside the nvcp, then inside the game vsync off and the nvidia reflex off, i get 138fps as expected and everything works fine, but i have a question, should i play like this or disable the vsync in the nvcp for cs2 to go to 200 or 300fps? because as I understand the more fps the less frametime in ms, now I would have about 7.2ms but if I unlimit it and I go to 250fps I would have 4ms, is this really so and would it make any difference?

HarmVJ
Member
HarmVJ

So windows 10 has something called VRR in the graphics setting. Should it be used in tandem with G-Sync + NVCP Vsync. Some sources and review just say to turn it on along with g-sync.

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