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.



1182 Comments For “G-SYNC 101”

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kermirz
Member
kermirz

Hello, sorry if similar ask was here.

I got AOC 24g2u and I turn on g sync. But I have V sync off. Now I reading your guide.

So, if I want to use g sync perfectly, I need to turn on V sync and G sync and use limmiter FPS?

What settings I need to i.e csgo? When I want not some input lags etc. Now i have 200-300 fps in csgo.

If I understood correcly, when I have 160 fps in game, G sync does not work?

Techno Peasant
Member
Techno Peasant

Has anyone else had issues attempting to set and use “Gsync – Application Mode” in nvidia inspector? I’ve been attempting to run Path of Exile in Borderless Window mode, but with both “Gsync – Application Mode” and “GSYNC – Global Mode” set to “Fullscreen and Windowed” in it’s nvidia inspector profile. Despite this, gsync never kicks in, and I’m forced to use “Fullscreen” mode within PoE to get gsync to work.

Joselaba97
Member
Joselaba97

After months of testing, I believe I have found the optimal settings implementing gsync in Gears 5. I’m currently an EE student, so this is the only game I have time to play competitively. I currently have the following settings enabled in NVCP, Windows, and Gears 5 respectively:

Monitor: G-Sync Compatible
Refresh Rate: Highest Available
Low Latency Mode: ON
Vertical Sync: Fast
G-Sync: Enabled for Full Screen Mode
Game Mode: ON
Variable Refresh Rate: ON
Hardware Enabled GPU Scheduling: ON
Reduced Buffering: ON
ASYNC Compute: OFF
Frame Rate Limit (config file): 237
Textures and Shadows are a Blend of Ultra and Medium settings for best visual fidelity and performance

Using the In-game benchmark, I would typically get 8,000 – 8,500 frames rendered using your optimal gsync settings. However, when I used these settings shown, I got 10,250 frames at a 98% GPU bound. And now I am getting 180-236.97 fps in a match and even while streaming. I would typically get 140-180 using the previous settings, your optimal settings. I feel like this is a valid discovery, however, I have no methodology of testing whether or not the input lag was increased using the “fast” vsync setting in conjunction with gsync. There is also no blatant stuttering in-game, but it’s also hard to tell since there is no way to differentiate server and computer performance.

Please let me know what you think and whether or not you are able to test this.

weszh
Member
weszh

Im confused at one part. Im playing Valorant btw. So i set my Vsync(nvidia control panel) to fast, Gsync On. what about in game setting? Should i turn on Vsync too or off? I saw and article saying turn on Nvidia cntrl panel ones and disable ingame ones. Which confuse me. Any answer is highly appreciated.

ZamoraFTW
Member
ZamoraFTW

Three days ago I bought the Asus vg27aq monitor, which brings Adaptive Sync technology which makes it GSync compatible. I really love this monitor, the color are pretty good, the 2k@144hz is awesome BUT when I open a game in full screen mode, the monitor flickers once and then goes black (I still get sound from the game).

Some data I managed to test and anote:

– Disabling Gsync from the Nvidia panel fixes, but not an acceptable solution.

– If I put the game in windowed borderless it also solves it but I don’t know if Gsync is working there or not.

– If I have only the 2k monitor plugged in, the problems only occurs like 20% of the time.

My setup is dual monitor, one over displayport 2k@144 and the other with HDMI 1080p@60hz, my GPU is a Gigabyte Geforce 1080ti Gaming OC

I have ordered an 1.4 displayport cable but until it arrive I wanna ask for help.

pasima03
Member
pasima03

Hi, i play competitive FIFA 20 (in future 21) Pro Club Mode on DX12.
My System:
Moinitor: AOC Agon AG271QG @ 2560×1440
CPU: AMD Ryzen 5 3600XT
MoBo: Gigabyte B550 Aorus Master
RAM: 32GB (2x 16384MB) G.Skill Trident Z Neo DDR4-3600 DIMM CL16-16-16-36
GraKa: 8GB Gigabyte GeForce RTX 2070 SUPER Gaming OC 3X 8

Whats the best Settings for a low Input Lag. Actually i have Gsync Fullscreen on and V-Sync on. How i get the lowest possible Input Lag?

Thank you so much for your help. I tested a lot of settings but i dont get what i want :=)

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