Gsync Compatible display + Vsync = Input Lag (s2721dgf)

Everything about latency. This section is mainly user/consumer discussion. (Peer-reviewed scientific discussion should go in Laboratory section). Tips, mouse lag, display lag, game engine lag, network lag, whole input lag chain, VSYNC OFF vs VSYNC ON, and more! Input Lag Articles on Blur Busters.
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casualnoncasual
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Joined: 24 Jul 2021, 16:51

Gsync Compatible display + Vsync = Input Lag (s2721dgf)

Post by casualnoncasual » 06 Sep 2022, 07:34

Hello,

I was wondering if I could get some help figuring out if my Gsync-compatible monitor isn't compatible with the gsync + limit fps below refresh rate method because of frame-time spikes (introduces a lot of vsync lag, I think). I usually play Apex Legends and cap my FPS with RTSS at 155 (10 fps below refresh). Still, when I turn on my monitor refresh rate display, it shows that the refresh rate varies a lot and goes up to max (165hz) pretty frequently, which I presume would cause vsync lag. As a result, I've been testing with a 144hz cap, it feels like there is less input lag, but I can't tell if it's a placebo. However, it doesn't look as smooth, so I'm wondering if anyone experienced could tell me what they think + if I should invest in a new monitor with a gsync module to mitigate the input lag?

Here's a reddit post that explains someone else similar experience in more detail:
https://www.reddit.com/r/apexlegends/co ... servation/

Thanks

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jorimt
Posts: 2635
Joined: 04 Nov 2016, 10:44
Location: USA

Re: Gsync Compatible display + Vsync = Input Lag (s2721dgf)

Post by jorimt » 06 Sep 2022, 08:45

casualnoncasual wrote:
06 Sep 2022, 07:34
I usually play Apex Legends and cap my FPS with RTSS at 155 (10 fps below refresh). Still, when I turn on my monitor refresh rate display, it shows that the refresh rate varies a lot and goes up to max (165hz) pretty frequently, which I presume would cause vsync lag. As a result, I've been testing with a 144hz cap, it feels like there is less input lag, but I can't tell if it's a placebo.

[...]

Here's a reddit post that explains someone else similar experience in more detail:
https://www.reddit.com/r/apexlegends/co ... servation/
1) G-SYNC does not address frametime spikes, which stem from the system-side (that occur with or without it enabled), and 2) 155 FPS RTSS at 165Hz should be plenty for Apex.

As for FreeSync monitor OSD refresh rate meters, they are infamously unreliable and often include LFC multiples in their readout. As such, they shouldn't be relied on as an accurate moment-to-moment gauge of average FPS.

They're only really good for verifying whether G-SYNC is currently engaged; fluctuating = engaged, static at max refresh rate = unengaged.

As for the reddit thread, I don't recommend a -3 FPS limit, I recommend a minimum -3 FPS limit. I.E. sometimes the limit should be lower than that, but it is highly system/game/limiter-dependent, so I couldn't fit into a single blanketed recommendation.
(jorimt: /jor-uhm-tee/)
Author: Blur Busters "G-SYNC 101" Series

Displays: ASUS PG27AQN, LG 48C4 Scaler: RetroTINK 4k Consoles: Dreamcast, PS2, PS3, PS5, Switch 2, Wii, Xbox, Analogue Pocket + Dock VR: Beyond, Quest 3, Reverb G2, Index OS: Windows 11 Pro Case: Fractal Design Torrent PSU: Seasonic PRIME TX-1000 MB: ASUS Z790 Hero CPU: Intel i9-13900k w/Noctua NH-U12A GPU: GIGABYTE RTX 4090 GAMING OC RAM: 32GB G.SKILL Trident Z5 DDR5 6400MHz CL32 SSDs: 2TB WD_BLACK SN850 (OS), 4TB WD_BLACK SN850X (Games) Keyboards: Wooting 60HE, Logitech G915 TKL Mice: Razer Viper Mini SE, Razer Viper 8kHz Sound: Creative Sound Blaster Katana V2 (speakers/amp/DAC), AFUL Performer 8 (IEMs)

casualnoncasual
Posts: 3
Joined: 24 Jul 2021, 16:51

Re: Gsync Compatible display + Vsync = Input Lag (s2721dgf)

Post by casualnoncasual » 06 Sep 2022, 09:43

Thank you for the detailed response. It helped clear up a lot... I think apex servers are just laggy and inconsistent, it might not be my setup that's causing it. I'll stick to 155fps cap Gsync + Vsync as it feels smoother to look at.

drlalamso
Posts: 1
Joined: 06 Sep 2022, 12:15

Re: Gsync Compatible display + Vsync = Input Lag (s2721dgf)

Post by drlalamso » 06 Sep 2022, 12:34

jorimt wrote:
06 Sep 2022, 08:45
casualnoncasual wrote:
06 Sep 2022, 07:34
I usually play Apex Legends and cap my FPS with RTSS at 155 (10 fps below refresh). Still, when I turn on my monitor refresh rate display, it shows that the refresh rate varies a lot and goes up to max (165hz) pretty frequently, which I presume would cause vsync lag. As a result, I've been testing with a 144hz cap, it feels like there is less input lag, but I can't tell if it's a placebo.

[...]

Here's a reddit post that explains someone else similar experience in more detail:
https://www.reddit.com/r/apexlegends/co ... servation/
1) G-SYNC does not address frametime spikes, which stem from the system-side (that occur with or without it enabled), and 2) 155 FPS RTSS at 165Hz should be plenty for Apex.

As for FreeSync monitor OSD refresh rate meters, they are infamously unreliable and often include LFC multiples in their readout. As such, they shouldn't be relied on as an accurate moment-to-moment gauge of average FPS.

They're only really good for verifying whether G-SYNC is currently engaged; fluctuating = engaged, static at max refresh rate = unengaged.

As for the reddit thread, I don't recommend a -3 FPS limit, I recommend a minimum -3 FPS limit. I.E. sometimes the limit should be lower than that, but it is highly system/game/limiter-dependent, so I couldn't fit into a single blanketed recommendation.
OT: I read some threads you replied to. The "XG27AQM vs. PG279QM" to be exact and was wondering if you found any of these equivalent to the BenQ XL2456 in terms of image clarity / response time. Or maybe the AW2721D? Used TN Panels for my hole life and since the IPS ones are, as it seems atleast, comparabile to TN´s now i wanted to change. Since i have to deal with alot of variable Frames in games i rather want a gsync than a dyac montior but also not missing out of the clarity. Looking forward hearing from you and thanks in advance

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jorimt
Posts: 2635
Joined: 04 Nov 2016, 10:44
Location: USA

Re: Gsync Compatible display + Vsync = Input Lag (s2721dgf)

Post by jorimt » 06 Sep 2022, 14:36

drlalamso wrote:
06 Sep 2022, 12:34
OT: I read some threads you replied to. The "XG27AQM vs. PG279QM" to be exact and was wondering if you found any of these equivalent to the BenQ XL2456 in terms of image clarity / response time. Or maybe the AW2721D? Used TN Panels for my hole life and since the IPS ones are, as it seems atleast, comparabile to TN´s now i wanted to change. Since i have to deal with alot of variable Frames in games i rather want a gsync than a dyac montior but also not missing out of the clarity. Looking forward hearing from you and thanks in advance
For any OT comments in the future, make a thread or PM me here ("CONTACT JORIMT" section and "PM: Send private message" via my profile page).

Short answer is I've only personally owned and used the below gaming "monitors:"

1. Acer Predator XB252Q (1st-gen native G-SYNC 1080p 240Hz TN)
2. Acer XB271HU (1st-gen native G-SYNC 1440p 165Hz IPS)
3. ASUS Predator PG279Q (1st-gen native G-SYNC 1440p 165Hz IPS)
4. ASUS Predator PG279QM (2nd-gen native G-SYNC 1440p 240Hz IPS)
5. LG 48CX (1st-gen G-SYNC Compatible 4k 120Hz OLED)

Anything else I'd be speculating on based on available reviews and numbers like anyone else (albiet with a little more educated knowledge to interpret them).

Anyway, again, if you want to continue this convo, PM me.
(jorimt: /jor-uhm-tee/)
Author: Blur Busters "G-SYNC 101" Series

Displays: ASUS PG27AQN, LG 48C4 Scaler: RetroTINK 4k Consoles: Dreamcast, PS2, PS3, PS5, Switch 2, Wii, Xbox, Analogue Pocket + Dock VR: Beyond, Quest 3, Reverb G2, Index OS: Windows 11 Pro Case: Fractal Design Torrent PSU: Seasonic PRIME TX-1000 MB: ASUS Z790 Hero CPU: Intel i9-13900k w/Noctua NH-U12A GPU: GIGABYTE RTX 4090 GAMING OC RAM: 32GB G.SKILL Trident Z5 DDR5 6400MHz CL32 SSDs: 2TB WD_BLACK SN850 (OS), 4TB WD_BLACK SN850X (Games) Keyboards: Wooting 60HE, Logitech G915 TKL Mice: Razer Viper Mini SE, Razer Viper 8kHz Sound: Creative Sound Blaster Katana V2 (speakers/amp/DAC), AFUL Performer 8 (IEMs)

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