Is my LG 27GL83A-B broken or is it just me ?

Talk about NVIDIA G-SYNC, a variable refresh rate (VRR) technology. G-SYNC eliminates stutters, tearing, and reduces input lag. List of G-SYNC Monitors.
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Djbofo
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Is my LG 27GL83A-B broken or is it just me ?

Post by Djbofo » 27 Sep 2021, 18:03

Hello everyone!

I have an LG 27GL83A-B 144hz with GSYNC on and VSYNC off. Everything else is default.

Game runs smooth but once the frames per second are around 135-180 the is noticeable tearing. The game (Destiny 2) usually runs around 130-140 casual but in competitive (crucible) I bump up graphic settings to allow up to 210fps.
Even around 200 there’s is a choppy look to the scene when looking around.

I have an Alienware 2421hf 240hz and everything has been perfectly smooth, never had issues. Rocket league at 250fps looked smooth as well and that’s just 10 more fps than refresh rate! Also side note, rocket league feels sluggish on the LG.

I know a few things… more frames can be useful for better input lag, gsync only works properly for fps under refresh rate.

Scenario #1: cap my fps at 141 and enjoy smooth gameplay BUT at 141fps with gsync on.
Scenario #2: let my frames go wild and deal with the tearing with only gsync on.
Scenario #3: get that ASUS XG27AQM or AW 2721D for 240hz… IF it’s actually the refresh rate causing these issues.

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jorimt
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Re: Is my LG 27GL83A-B broken or is it just me ?

Post by jorimt » 27 Sep 2021, 19:09

Djbofo wrote:
27 Sep 2021, 18:03
I have an LG 27GL83A-B 144hz with GSYNC on and VSYNC off. Everything else is default.

Game runs smooth but once the frames per second are around 135-180 the is noticeable tearing.
Your LG isn't broken, as 1) a 144Hz G-SYNC display (with LFC support) has an effective 0 to 144 FPS VRR range, so as you said you already knew, if you have G-SYNC on + V-SYNC off without a minimum 141 FPS limit and the framerate exceeds the refresh rate, G-SYNC will disengage and full tearing will occur, and 2) G-SYNC can still tear with framerates within the refresh rate if the V-SYNC "option" (which is actually a function of G-SYNC tearing prevention within the refresh rate) is off.

Read my second Closing FAQ entry for complete details:
https://blurbusters.com/gsync/gsync101- ... ttings/15/
Wait, why should I enable V-SYNC with G-SYNC again? And why am I still seeing tearing with G-SYNC enabled and V-SYNC disabled? Isn’t G-SYNC suppose to fix that?

The answer is frametime variances.

“Frametime” denotes how long a single frame takes to render. “Framerate” is the totaled average of each frame’s render time within a one second period.

At 144Hz, a single frame takes 6.9ms to display (the number of which depends on the max refresh rate of the display, see here), so if the framerate is 144 per second, then the average frametime of 144 FPS is 6.9ms per frame.

In reality, however, frametime from frame to frame varies, so just because an average framerate of 144 per second has an average frametime of 6.9ms per frame, doesn’t mean all 144 of those frames in each second amount to an exact 6.9ms per; one frame could render in 10ms, the next could render in 6ms, but at the end of each second, enough will hit the 6.9ms render target to average 144 FPS per.

So what happens when just one of those 144 frames renders in, say, 6.8ms (146 FPS average) instead of 6.9ms (144 FPS average) at 144Hz? The affected frame becomes ready too early, and begins to scan itself into the current “scanout” cycle (the process that physically draws each frame, pixel by pixel, left to right, top to bottom on-screen) before the previous frame has a chance to fully display (a.k.a. tearing).

G-SYNC + V-SYNC “Off” allows these instances to occur, even within the G-SYNC range, whereas G-SYNC + V-SYNC “On” (what I call “frametime compensation” in this article) allows the module (with average framerates within the G-SYNC range) to time delivery of the affected frames to the start of the next scanout cycle, which lets the previous frame finish in the existing cycle, and thus prevents tearing in all instances.

And since G-SYNC + V-SYNC “On” only holds onto the affected frames for whatever time it takes the previous frame to complete its display, virtually no input lag is added; the only input lag advantage G-SYNC + V-SYNC “Off” has over G-SYNC + V-SYNC “On” is literally the tearing seen, nothing more.

For further explanations on this subject see part 1 “Control Panel,” part 4 “Range,” and part 6 “G-SYNC vs. V-SYNC OFF w/FPS Limit” of this article, or read the excerpts below…
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Djbofo wrote:
27 Sep 2021, 18:03
The game (Destiny 2) usually runs around 130-140 casual but in competitive (crucible) I bump up graphic settings to allow up to 210fps.
Even around 200 there’s is a choppy look to the scene when looking around.
Tearing at 144Hz 200 FPS can make things look "choppy."
Djbofo wrote:
27 Sep 2021, 18:03
I have an Alienware 2421hf 240hz and everything has been perfectly smooth, never had issues. Rocket league at 250fps looked smooth as well and that’s just 10 more fps than refresh rate! Also side note, rocket league feels sluggish on the LG.
240Hz has a faster scanout rate than 144Hz (4.2ms vs. 6.9ms), and refreshes 96 times more per second, so tearing artifacts are less noticeable, and general smoothness/responsiveness is increased. The same would be true for 360Hz over 240Hz, and 480Hz over 360Hz, and so on...
(jorimt: /jor-uhm-tee/)
Author: Blur Busters "G-SYNC 101" Series

Displays: ASUS PG27AQN, LG 48CX 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)

Djbofo
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Re: Is my LG 27GL83A-B broken or is it just me ?

Post by Djbofo » 28 Sep 2021, 13:04

So basically when people (me) buy the 240Hz monitor, they aren’t ONLY buying the fact that it can refresh faster, it’s so that the range of gsync/freesync is greater vs for example a 144Hz monitor.

So do people just have to deal with tearing if their frames go beyond 144Fps if it’s uncapped? I guess that’s the price they pay i assume.
The alternative is to turn on gsync and vsync (on NVCP) and cap frames to 141… giving up those extra frames for “decrease in input lag”

Will the optimal settings mess with input lag ? I like the visuals on my 27in LG especially for destiny but for competitive, if input lag is increased, I will either buy 240Hz monitor or just switch it over every time to my AW monitor.

Thank you for your help. (I’ve tried looking thru forums but i can’t seem to find a scenario like mine to compare)

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jorimt
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Re: Is my LG 27GL83A-B broken or is it just me ?

Post by jorimt » 28 Sep 2021, 14:59

Djbofo wrote:
28 Sep 2021, 13:04
So basically when people (me) buy the 240Hz monitor, they aren’t ONLY buying the fact that it can refresh faster, it’s so that the range of gsync/freesync is greater vs for example a 144Hz monitor.
Correct.
Djbofo wrote:
28 Sep 2021, 13:04
So do people just have to deal with tearing if their frames go beyond 144Fps if it’s uncapped? I guess that’s the price they pay i assume.
G-SYNC controls the refresh "rate." If the framerate exceeds the refresh rate, G-SYNC no longer has anything to control, and thus disengages until the framerate falls within the refresh rate again. It's a literal physical limitation.

As you pointed out already, there's no way to "fix" this other than to obtain a display with a higher max refresh rate, which will increase the effective VRR range.
Djbofo wrote:
28 Sep 2021, 13:04
The alternative is to turn on gsync and vsync (on NVCP) and cap frames to 141… giving up those extra frames for “decrease in input lag”
The fastest no-tear single frame delivery possible is G-SYNC + V-SYNC + minimum -3 FPS of the given max refresh rate. Any further decrease of input lag requires tearing.
Djbofo wrote:
28 Sep 2021, 13:04
Will the optimal settings mess with input lag ? I like the visuals on my 27in LG especially for destiny but for competitive, if input lag is increased, I will either buy 240Hz monitor or just switch it over every time to my AW monitor.
Any "input lag" G-SYNC on + V-SYNC on has over G-SYNC on + V-SYNC off or G-SYNC off + V-SYNC off at the same framerate within the refresh rate is a lack of tearing, nothing more.
Djbofo wrote:
28 Sep 2021, 13:04
Thank you for your help. (I’ve tried looking thru forums but i can’t seem to find a scenario like mine to compare)
You're welcome.

And if you ever want a more in-depth understanding of G-SYNC behavior, my G-SYNC 101 article is always available here:
https://blurbusters.com/gsync/gsync101- ... -settings/
(jorimt: /jor-uhm-tee/)
Author: Blur Busters "G-SYNC 101" Series

Displays: ASUS PG27AQN, LG 48CX 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)

Djbofo
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Joined: 27 Sep 2021, 17:45

Re: Is my LG 27GL83A-B broken or is it just me ?

Post by Djbofo » 28 Sep 2021, 19:56

Wait, one more thing haha.
Why not JUST turn on GSYNC and cap -3fps from total refresh rate ? Why does vsync need to be turned on with above combination ?

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jorimt
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Re: Is my LG 27GL83A-B broken or is it just me ?

Post by jorimt » 28 Sep 2021, 20:10

Djbofo wrote:
28 Sep 2021, 19:56
Wait, one more thing haha.
Why not JUST turn on GSYNC and cap -3fps from total refresh rate ? Why does vsync need to be turned on with above combination ?
Did you read the quote from my article in this comment?
viewtopic.php?f=5&t=9157&p=72254#p72222

The V-SYNC "option" isn't actually V-SYNC when paired with G-SYNC with framerates inside the refresh rate. It's part of G-SYNC tearing prevention. G-SYNC on + V-SYNC off is actually only partial G-SYNC and can still tear with a -3 FPS limit. This point is the most commonly misunderstood where G-SYNC operation is concerned.

G-SYNC is fundamentally & technically still V(ertical)-SYNC in all but one way; it syncs the display to the GPU output instead of the GPU output to the display.

See also:
https://blurbusters.com/gsync/gsync101- ... -settings/
G-SYNC & V-SYNC

G-SYNC (GPU Synchronization) works on the same principle as double buffer V-SYNC; buffer A begins to render frame A, and upon completion, scans it to the display. Meanwhile, as buffer A finishes scanning its first frame, buffer B begins to render frame B, and upon completion, scans it to the display, repeat.

The primary difference between G-SYNC and V-SYNC is the method in which rendered frames are synchronized. With V-SYNC, the GPU’s render rate is synchronized to the fixed refresh rate of the display. With G-SYNC, the display’s VRR (variable refresh rate) is synchronized to the GPU’s render rate.

Upon its release, G-SYNC’s ability to fall back on fixed refresh rate V-SYNC behavior when exceeding the maximum refresh rate of the display was built-in and non-optional. A 2015 driver update later exposed the option.

This update led to recurring confusion, creating a misconception that G-SYNC and V-SYNC are entirely separate options. However, with G-SYNC enabled, the “Vertical sync” option in the control panel no longer acts as V-SYNC, and actually dictates whether, one, the G-SYNC module compensates for frametime variances output by the system (which prevents tearing at all times. G-SYNC + V-SYNC “Off” disables this behavior; see G-SYNC 101: Range), and two, whether G-SYNC falls back on fixed refresh rate V-SYNC behavior; if V-SYNC is “On,” G-SYNC will revert to V-SYNC behavior above its range, if V-SYNC is “Off,” G-SYNC will disable above its range, and tearing will begin display wide.

Within its range, G-SYNC is the only syncing method active, no matter the V-SYNC “On” or “Off” setting.
(jorimt: /jor-uhm-tee/)
Author: Blur Busters "G-SYNC 101" Series

Displays: ASUS PG27AQN, LG 48CX 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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