G-SYNC 101: G-SYNC Ceiling vs. FPS Limit


How Low Should You Go?

Blur Busters was the world’s first site to test G-SYNC in Preview of NVIDIA G-SYNC, Part #1 (Fluidity) using an ASUS VG248QE pre-installed with a G-SYNC upgrade kit. At the time, the consensus was limiting the fps from 135 to 138 at 144Hz was enough to avoid V-SYNC-level input lag.

However, much has changed since the first G-SYNC upgrade kit was released; the Minimum Refresh Range wasn’t in place, the V-SYNC toggle had yet to be exposed, G-SYNC did not support borderless or windowed mode, and there was even a small performance penalty on the Kepler architecture at the time (Maxwell and later corrected this).

My own testing in my Blur Busters Forum thread found that just 2 FPS below the refresh rate was enough to avoid the G-SYNC ceiling. However, now armed with improved testing methods and equipment, is this still the case, and does the required FPS limit change depending on the refresh rate?

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, just 2 FPS below the refresh rate is indeed still enough to avoid the G-SYNC ceiling and prevent V-SYNC-level input lag, and this number does not change, regardless of the maximum refresh rate in use.

To leave no stone unturned, an “at” FPS, -1 FPS, -2 FPS, and finally -10 FPS limit was tested to prove that even far below -2 FPS, no real improvements can be had. In fact, limiting the FPS lower than needed can actually slightly increase input lag, especially at lower refresh rates, since frametimes quickly become higher, and thus frame delivery becomes slower due to the decrease in sustained framerates.

As for the “perfect” number, going by the results, and taking into consideration variances in accuracy from FPS limiter to FPS limiter, along with differences in performance from system to system, a -3 FPS limit is the safest bet, and is my new recommendation. A lower FPS limit, at least for the purpose of avoiding the G-SYNC ceiling, will simply rob frames.



2778 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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