OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

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.
pzkY
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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by pzkY » 02 Apr 2023, 05:41

pzkY wrote:
01 Apr 2023, 06:12
I will do a clean driver reinstall with DDU and see if it still persists
Did that just now and the issue is "gone", as long as you're above 50Hz. I think the monitors VRR was from 48-240Hz, so if you get to close to the lowest range, it also flickers. If you get out of the range (below 50Hz), the refresh rate goes crazy again, obviously.

Conclusion to me: LG could fix this by "optimizing" the gamma curves for each refresh rate in the whole VRR range. That way the darker colors wouldn't be washed out as well, if it's at the lower spectrum darker areas are quite bright with 55Hz, compared to 240Hz.
It may not be gone completely, due to variances in models, but it would be way better than it is now, where 55Hz looks like a TN-panel in dark levels.
I wonder if ASUS did it different with their OLED model, since it has the same panel..
jorimt wrote:
31 Mar 2023, 11:30
That said, to rule out any G-SYNC configuration issues, ensure you're using G-SYNC "Enable for full screen mode" + NVCP Vertical sync "On" + a framerate limit at least 3 frames below the current physical refresh rate (I assume you're using a 50 FPS RTSS limit in the videos).
Did that, exactly as you described, since this offers the lowest latency and best compatibility with games, iirc.
jorimt wrote:
31 Mar 2023, 11:30
What operating system are you on, and have you ever messed with regedits for fullscreen optimizations or the like? Because it looks potentially like a flip model issue; try also ruling out MPO:
viewtopic.php?f=5&t=10730&p=87330&hilit=mpo#p87330
Windows 10, but a modified one (Ghost), though I never had G-Sync issues on it.
I didn't do any messing with fullscren optimizations, since all my testings with with it gave me less fps in games and more stutters, so I left it at that. Though that's probably due to my CPU (TR2920X), since results on my old i5 3570k@5GHz were different.
jorimt wrote:
31 Mar 2023, 11:30
Long story short, the worse or more sporadic the frametime performance is in a game, the worse the near-black OLED VRR flicker will be.

The only way to avoid this on current-gen LG OLED panels during VRR operation is to use an external limiter like RTSS to set an FPS limit that can be sustained 99% of the time in the given game.

I.E. you want the RTSS limit to be the framerate's limiting factor the majority of the time. As long as it is, RTSS will stabilize frametime performance, which should reduce the near-black flicker to a minimum.
One last question. RTSS vs NVCP frame limiter, how do they compare?
If I recall correctly RTSS has a 1-frame-latency and nvidia inspector had 2-frames-latency (very old information, might be different now). So I'm kind of curious if the result with NVCP and RTSS would be the same in the end, or if one has the upper hand.

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jorimt
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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by jorimt » 02 Apr 2023, 09:51

pzkY wrote:
02 Apr 2023, 05:41
Did that just now and the issue is "gone", as long as you're above 50Hz. I think the monitors VRR was from 48-240Hz, so if you get to close to the lowest range, it also flickers. If you get out of the range (below 50Hz), the refresh rate goes crazy again, obviously.
I use DDU to clean uninstall in safe mode each driver release myself.

48Hz may be the monitor's lowest physical VRR range, but below it, driver-level LFC should then trigger for a virtual "down to 0Hz" VRR range via refresh doubling.

That said, it's possible on top of OLED flicker, the monitor also experiences LFC flicker at lower framerates by starting it too late. This may or may not be able to be adjusted via CRU (by raising the minimum range from 48Hz to, say, 60Hz to start LFC earlier, for instance).
pzkY wrote:
02 Apr 2023, 05:41
Conclusion to me: LG could fix this by "optimizing" the gamma curves for each refresh rate in the whole VRR range. That way the darker colors wouldn't be washed out as well, if it's at the lower spectrum darker areas are quite bright with 55Hz, compared to 240Hz.
It may not be gone completely, due to variances in models, but it would be way better than it is now, where 55Hz looks like a TN-panel in dark levels.
I wonder if ASUS did it different with their OLED model, since it has the same panel..
I've already brought up the possibility of a gamma LUT in past conversations with others about this, but it would probably have to be hardware-level and implemented by the panel (which is usually reused across monitor models), not monitor manufacturers.

Think of it this way; OLED VRR support has been around for three years, and over that time, there have been multiple panel revisions for TVs and monitors from both LG (WOLED) and Samsung (QD-OLED), and OLED-specific VRR flicker has yet to be addressed.

That and WOLED and QD-OLED are completely different OLED-types from entirely separate companies and both have the identical issue.

I.E. OLED was apparently not created with VRR in mind and it shows, so I'm not holding my breath on a solution any time soon, especially seeing as LG would resort to putting a disclaimer about VRR flicker in their manual rather than address it at the hardware-level after multiple panel revisions over the years.

It's obviously not a trivial issue, else I assume they would have fixed it by now.

Basically, don't expect it to be resolved or even mitigated on your model with a future firmware update; you're 99.9% stuck with it if you keep that model (or buy any other TV/monitor featuring an OLED panel this year).
pzkY wrote:
02 Apr 2023, 05:41
Windows 10, but a modified one (Ghost), though I never had G-Sync issues on it.
Worth a mention, regardless, since there's always the possibility a custom/modified Windows install could affect something over stock.
pzkY wrote:
02 Apr 2023, 05:41
One last question. RTSS vs NVCP frame limiter, how do they compare?
If I recall correctly RTSS has a 1-frame-latency and nvidia inspector had 2-frames-latency (very old information, might be different now). So I'm kind of curious if the result with NVCP and RTSS would be the same in the end, or if one has the upper hand.
Nvidia added a new "Max Frame Rate" limiter in driver version 441.87, which was tested to be comparable to RTSS in both frametime performance and latency upon its release.

Whether Nvidia modified it further since is the question, so I'm not 100% sure if it still limits by frametime like RTSS does, but you can always try it and see what results you get vs. RTSS. You should be able to simply "see" any frametime performance differences by eye where OLED VRR flicker and/or stutter is concerned.
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Stitch7
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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by Stitch7 » 04 Apr 2023, 05:29

I got the monitor and had multiple LCDs before it is like LCD flicker. The brightness just straight up increases and decreases making it look darker / brighter. It might be switching so fast that i dont notice the black frame between refreshes but i dont think it is that. It might just be a bug.

Edit did the MPO thing and set Vsync on and now the flicker only occurs when experiencing fps drops in menus and loading screens. Still thinking whether the tradeoff matters in a game like rocket league (game is FSE and has FSO enabled, tested both and for a frequent alt-tabber like me it is definitely the better setup).

Thank you for pointing that out!

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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by Pootklopp » 09 Apr 2023, 15:24

I did some more testing, is RTSS the only limiter that will work as you described? I was using nvcp to try some different things and still could not get steady frame times. I think Tarkov is exceptionally bad with this monitor because nothing I did got rid of the flicker. I tried caps at 230, 200, & 140. All of them produced the same results. This was tested in the games Hideout, so I was able to keep those frames easily. The frame time however would fluctuate very consistently for each.

Some side note about tarkov if you're not familiar. The only way to uncap fps in game is to turn on vsync in game. With it off (the 140 cap test) I was still getting issue.

Thoughts? Any suggestions?


:!:
jorimt wrote:
01 Apr 2023, 19:58
Pootklopp wrote:
01 Apr 2023, 16:31
Hello, I just picked this monitor up and have noticed some flickering (only really in Escape from tarkov) in my limited testing. If I find the flickering to be too much in a game do you have a recommendation for optimal settings for games where I would want to stop the flicker?
I have answered that more than once in this thread. See:
jorimt wrote:
03 Feb 2023, 12:07
Long story short, the worse or more sporadic the frametime performance is in a game, the worse the near-black OLED VRR flicker will be.

The only way to avoid this on current-gen LG OLED panels during VRR operation is to use an external limiter like RTSS to set an FPS limit that can be sustained 99% of the time in the given game.

I.E. you want the RTSS limit to be the framerate's limiting factor the majority of the time. As long as it is, RTSS will stabilize frametime performance, which should reduce the near-black flicker to a minimum.
jorimt wrote:
30 Mar 2023, 09:24
As I noted previously in this topic, with current-gen OLED, this form of flicker will happen during VRR operation whenever the frametime performance is sporadic enough. It's not directly framerate related.

You'll need to determine your 99% sustainable average framerate (per game) and cap just below it with RTSS to ensure steady frametime performance during VRR operation, which should mitigate the near-black VRR flicker to acceptable levels.

Stitch7
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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by Stitch7 » 09 Apr 2023, 17:21

Pootklopp wrote:
09 Apr 2023, 15:24
I did some more testing, is RTSS the only limiter that will work as you described? I was using nvcp to try some different things and still could not get steady frame times. I think Tarkov is exceptionally bad with this monitor because nothing I did got rid of the flicker. I tried caps at 230, 200, & 140. All of them produced the same results. This was tested in the games Hideout, so I was able to keep those frames easily. The frame time however would fluctuate very consistently for each.

Some side note about tarkov if you're not familiar. The only way to uncap fps in game is to turn on vsync in game. With it off (the 140 cap test) I was still getting issue.

Thoughts? Any suggestions?


:!:
jorimt wrote:
01 Apr 2023, 19:58
Pootklopp wrote:
01 Apr 2023, 16:31
Hello, I just picked this monitor up and have noticed some flickering (only really in Escape from tarkov) in my limited testing. If I find the flickering to be too much in a game do you have a recommendation for optimal settings for games where I would want to stop the flicker?
I have answered that more than once in this thread. See:
jorimt wrote:
03 Feb 2023, 12:07
Long story short, the worse or more sporadic the frametime performance is in a game, the worse the near-black OLED VRR flicker will be.

The only way to avoid this on current-gen LG OLED panels during VRR operation is to use an external limiter like RTSS to set an FPS limit that can be sustained 99% of the time in the given game.

I.E. you want the RTSS limit to be the framerate's limiting factor the majority of the time. As long as it is, RTSS will stabilize frametime performance, which should reduce the near-black flicker to a minimum.
jorimt wrote:
30 Mar 2023, 09:24
As I noted previously in this topic, with current-gen OLED, this form of flicker will happen during VRR operation whenever the frametime performance is sporadic enough. It's not directly framerate related.

You'll need to determine your 99% sustainable average framerate (per game) and cap just below it with RTSS to ensure steady frametime performance during VRR operation, which should mitigate the near-black VRR flicker to acceptable levels.
As I said. You need to enable both gsync and freesync and then set the fps cap to 237. that is the only way it works for me

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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by jorimt » 09 Apr 2023, 18:45

Pootklopp wrote:
09 Apr 2023, 15:24
I did some more testing, is RTSS the only limiter that will work as you described?
RTSS is typically the most stable, since it limits framerate by frametime.
Pootklopp wrote:
09 Apr 2023, 15:24
I was using nvcp to try some different things and still could not get steady frame times. I think Tarkov is exceptionally bad with this monitor because nothing I did got rid of the flicker. I tried caps at 230, 200, & 140. All of them produced the same results. This was tested in the games Hideout, so I was able to keep those frames easily. The frame time however would fluctuate very consistently for each.
Frametime performance is entirely dependent on the given system spec's capabilities + game/engine/api + FPS limiting method being used.

As for NVCP vs. RTSS, while they should be close in most games, the latter will probably have consistently more stable frametime performance overall.

I'm assuming you can't use RTSS in Tarkov online-mode because of anti-cheat?

You could also be experiencing more than one form of flicker on that panel simultaneously; incompatibilities caused by MPO on certain configurations in certain games, poor default LFC threshold, OLED-specific VRR flicker due to gamma brightness shifts, etc, but I don't own the monitor (or Tarkov, for that matter), so I can't say anything for certain in your particular case other than, again, OLED in VRR mode will flicker without rock solid frametime performance.

If you want to more easily isolate and replicate the VRR flicker itself, you can use:
https://github.com/MattTS01/VRR_Flicker_Test_OpenGL
(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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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by Pootklopp » 10 Apr 2023, 16:13

jorimt wrote:
09 Apr 2023, 18:45

RTSS is typically the most stable, since it limits framerate by frametime.

Anti cheat in tarkov, that's funny.


Did some more testing with RTSS and had the exact same results. I see consistent swings from ~5ms jumping to 25ms. Decreasing my fps increases my lower numbers as expected. I'm guessing it's an optimization issue with tarkov, as it's a notoriously poorly optimized game.


If this is the only cause, would the only solution be to decrease fps until I equalize to the 25ms frame time? Which is something like 40fps? At this point I'm just curious more than anything. I'll also play around with tool you posted. Thanks for replies!

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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by jorimt » 10 Apr 2023, 20:04

Pootklopp wrote:
10 Apr 2023, 16:13
Anti cheat in tarkov, that's funny.
Yeah...I saw a recent YouTube video on the whole cheating situation. Apparently not then :lol:
Pootklopp wrote:
10 Apr 2023, 16:13
Did some more testing with RTSS and had the exact same results. I see consistent swings from ~5ms jumping to 25ms. Decreasing my fps increases my lower numbers as expected. I'm guessing it's an optimization issue with tarkov, as it's a notoriously poorly optimized game.

If this is the only cause, would the only solution be to decrease fps until I equalize to the 25ms frame time? Which is something like 40fps?
Hmm, if your framerate is truly able to be maintained at your set RTSS limit, then frametime should be near constant. If not, it means you're system is having a hard time remaining stable at the set limit, which can be due to your specs and/or game-specific issues.

I.E. if your average framerate drops below the set RTSS limit frequently enough (even if it only manifests as momentary drops), then you won't get the frametime stabilization benefits RTSS brings.

The Unity engine is also known not to work very well with VRR out-of-box.
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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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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by Pootklopp » 11 Apr 2023, 11:46

jorimt wrote:
10 Apr 2023, 20:04

Hmm, if your framerate is truly able to be maintained at your set RTSS limit, then frametime should be near constant. If not, it means you're system is having a hard time remaining stable at the set limit, which can be due to your specs and/or game-specific issues.

I.E. if your average framerate drops below the set RTSS limit frequently enough (even if it only manifests as momentary drops), then you won't get the frametime stabilization benefits RTSS brings.

The Unity engine is also known not to work very well with VRR out-of-box.
Here is a basic graph from one of my tests. The large spikes were alt tab and some game restarts. But overall the results were very consistent with every fps cap.

System is 5800x3d, 32gb ram, and 3080. I'll have to do some more digging and see if I can find anything.
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jorimt
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Re: OLED 240hz lg-27gr95qe-b and G-Sync Brightness Flicker

Post by jorimt » 11 Apr 2023, 13:07

Pootklopp wrote:
11 Apr 2023, 11:46
Here is a basic graph from one of my tests. The large spikes were alt tab and some game restarts. But overall the results were very consistent with every fps cap.
Your frametime performance in that graph is definitely not consistent enough, and will easily cause visible OLED VRR flicker. You're experiencing some serious sawtoothing; the frametime (bottom row) should be much flatter when the framerate is limited by RTSS or Nvidia MFR.

Do you get less VRR flicker in other games, and if so, what do their frametime graphs look like? Because if you aren't experiencing this in other games on the same system (or less so), it's likely game-specific.
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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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