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.



2611 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
Alex UA6
Member
Alex UA6

Hey brother, sorry to bother you again but I’m confused about one thing so in the game I play insurgency sandstorm it does not support freesync or Gsync. So in game I have limited my frames to my monitors, refresh rate, and enabled Vsync so I don’t get screen tearing. If I disable Vsync it’s unbearable. If in a newer game like modern warfare 2 would I want Vsync disabled? Also, if there’s anything you can tell me about the set up for insurgency, please feel free to let me know.

tbowly
Member
tbowly

is this normal? i have 60 stable fps on my 165hz Gsync monitor but the refresh rate keeps changing and is not stable, it keeps changing constantly to 50-80Hz happens to all of my games, and when a game has like 80 fps it keeps changing to 60-100Hz

tbowly
Member
tbowly

here’s the video of my problem: https://streamable.com/mm3oun

mustardpapi
Member
mustardpapi

I have a XL2546 so it is not G sync compatible. Should I still utilize 236 fps while using DYAC + nvidia V sync? Or are these settings G sync specific?

Alex UA6
Member
Alex UA6

Hey brother, my buddy, just picked up an LG ultra gear 165hz monitor with adaptive sync. I’m a little confused with the word adaptive sync. Is it just another word for free sync or G sync? I’m trying to understand if I should enable V sync when using adaptive sync. On my free sync display I enable V sync to eliminate screen tearing.

BNThuan
Member
BNThuan

Hi. Im playing ” crossfire” with monitor 165 hz . I setted up G sync “on” +V sync “on”+ limited fps “162” but in game fps still from 199-200 and lag. I have already changed setting NVCP but that problem has not improved. please give me advice. thanks

Karambol2K
Member
Karambol2K

Where did you cap fps? In game or in nvidia panel? I personally recommend RTSS for capping frames.

wpDiscuz