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.



3388 Comments For “G-SYNC 101”

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Sort by:   newest | oldest | most liked
TeeNam
Member
TeeNam

for competitive games like valorant, say for example the xg2431 monitor, would the g sync optimizations here be better than using strobing?
if the question still have some missing info for clarification, please ask me further.

epicjjoey
Member
epicjjoey

Can I use V-Sync in game or does it have to be in the nvcp?

xcheeezz
Member
xcheeezz

Hello! Is there any research on how a 2nd monitor with activated gsync influences latency?
Does disabling gsync for the 2nd display (which only shows youtube, discord, spotify etc.) result in lower/higher game latency? Or is this completely irrelevant?

Pessut
Member
Pessut

Hello! I have a monitor with 8ms pixel response time. If i enable NVIDIA Reflex will it also lower pixel response time making me see LESS motion blur when i move my mouse around in First Person Shooter for example?

JeritoBurrito
Member
JeritoBurrito

Appreciate the write up and sorry if this has been asked a million times. If I’m using an FPS limiter 3 below refresh rate should I still use in game reflex?

wpDiscuz