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.



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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