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Monitor Corsair XENEON 27QHD240 - G-SYNC flickering

Posted: 20 Jun 2023, 08:48
by Horog
I have problem with my new monitor Corsair XENEON 27QHD240 inside games with activated G-SYNC and Adaptive Sync. In dark scenes, the monitor flickers.

- Monitor is connected with Display Port cable.
- Nvidia driver is 536.23 (latest). In this driver I se my monitor is G-SYNC compatible. Older drivers don't show compatibility info with this monitor.

When I limit the FPS using the game settings or in the Nvidia drivers, the flickering does not go away.
When I switch the monitor to a lower refresh rate, the flickering doesn't go away either. Maybe it's a little weaker at a lower refresh rate.

I attached screenshots with my Nvidia driver settings. Video from game Overwatch 2 with flickering preview and the screenshot with the game settings.

I tested many options in many games, but nothing help.
Only one helps ..... when I deactivate G-SYNC.

This looks like Nvidia driver has wrong support of this monitor or Adaprive Sync inside this monitor is broken.

Next issue (inside Windows):
Some apps (I think .NET apps) as Razer Synapse 3 cause flickering, when move mouse over app active (e.g. menu) items, see attached video.

I wrote a ticket on Corsair, but I want to ask if someone could help. Thank you

Overwatch 2 flickering - FPS no limit
phpBB [video]


Overwatch 2 flickering - 120 FPS limit
phpBB [video]


Razer Synapse flickering
phpBB [video]


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Re: Monitor Corsair XENEON 27QHD240 - G-SYNC flickering

Posted: 20 Jun 2023, 13:02
by jorimt
Horog wrote:
20 Jun 2023, 08:48
In dark scenes, the monitor flickers.
Near-black OLED VRR flicker is a known issue. See a recent reply here:
viewtopic.php?f=2&t=12164#p94988

It's a hardware limitation exclusive to current-gen OLED and will happen to varying degrees on any monitor/model that contains an OLED panel when VRR is enabled.

Re: Monitor Corsair XENEON 27QHD240 - G-SYNC flickering

Posted: 20 Jun 2023, 14:34
by Horog
jorimt wrote:
20 Jun 2023, 13:02
Near-black OLED VRR flicker is a known issue.
Thanks for the direction. I've already read a lot of it on this forum today.

But I still need help / explanation.
If a game on my PC even in the most demanding situations reaches, for example, 150 FPS, I lock the FPS to 60 and let VRR run ..... I still see flickering even when I don't move in the game. The VRR indicator of the monitor shows an extremely fast changing number and it can be seen that the monitor is locked at 60 Hz, but sometimes the number jumps above 100 or even 200. And almost always, when this happens, flickering occurs. Why is this happening, I don't understand this behavior at all? It makes me think that the VRR in my monitor is malfunctioning somehow.

And the second topic.
When I disable G-SYNC and thus also VRR, all flickering problems disappear. My PC or the graphics card can't handle 240 FPS and more in games. If I leave G-SYNC off, how much visual or other problems will I have? Should I reduce the refresh rate of the monitor to 120 Hz? Or leave 240 Hz and simply not change anything? What is the best way to proceed if I want to operate this monitor without G-SYNC?

Thank you in advance for the explanation.

Re: Monitor Corsair XENEON 27QHD240 - G-SYNC flickering

Posted: 20 Jun 2023, 18:18
by jorimt
Horog wrote:
20 Jun 2023, 14:34

Thanks for the direction. I've already read a lot of it on this forum today.

But I still need help / explanation.
Did you read from any of the links in post I linked in my previous reply to you? Because it answered some of the below...
Horog wrote:
20 Jun 2023, 14:34
If a game on my PC even in the most demanding situations reaches, for example, 150 FPS, I lock the FPS to 60 and let VRR run ..... I still see flickering even when I don't move in the game.
Frametime performance is the issue with OLED VRR flicker, not average framerate. Did you try an RTSS instead of in-game limit and monitor the frametime graph via Afterburner?
Horog wrote:
20 Jun 2023, 14:34
The VRR indicator of the monitor shows an extremely fast changing number and it can be seen that the monitor is locked at 60 Hz, but sometimes the number jumps above 100 or even 200. And almost always, when this happens, flickering occurs. Why is this happening, I don't understand this behavior at all? It makes me think that the VRR in my monitor is malfunctioning somehow.
I have answered this before in the forums as well; that meter on FreeSync monitors in G-SYNC Compatible mode isn't very reliable. If that meter is fluctuating, VRR is active, and that's about all it's good for determining. Use a system-side FPS readout to determine the effective average variable refresh rate instead.
Horog wrote:
20 Jun 2023, 14:34
And the second topic.
When I disable G-SYNC and thus also VRR, all flickering problems disappear. My PC or the graphics card can't handle 240 FPS and more in games.
Again, this was explained in the links in my previous reply. OLED VRR flicker does not occur with VRR off.
Horog wrote:
20 Jun 2023, 14:34
If I leave G-SYNC off, how much visual or other problems will I have? Should I reduce the refresh rate of the monitor to 120 Hz? Or leave 240 Hz and simply not change anything? What is the best way to proceed if I want to operate this monitor without G-SYNC.
That's a question with branching answers, and will depend on what you're trying to achieve; least latency, least stutter, no tearing, etc?

Re: Monitor Corsair XENEON 27QHD240 - G-SYNC flickering

Posted: 20 Jun 2023, 18:34
by Horog
jorimt wrote:
20 Jun 2023, 18:18
Thanks again for your reply. Because it must be tiring to repeat the answers over and over again. There is a lot of information on this topic on the Internet and it is difficult to take it all in. Thank you for your time and patience!

Some info to my second topic. I'm trying to find the best way to set up the monitor without G-SYNC, because the flickering is terribly annoying. I like the monitor and its parameters compared to IPS are amazing. I was interested in the opinion of how you would proceed if there was no G-SYNC and 240 FPS and you would not be able to achieve more. So that the gaming experience is as good as possible. That's all. I don't have any particular preference. I play competitive games like Overwatch 2, but also a big MMORPG.

Re: Monitor Corsair XENEON 27QHD240 - G-SYNC flickering

Posted: 20 Jun 2023, 19:26
by Chief Blur Buster
You can configure GSYNC to be OFF for some games and ON for others.

Some games really look good with GSYNC on the Cosair Xeneon Flex -- like System Shock. You simply have to make sure you keep framerates 100fps or above to prevent the flickering. The experience with GSYNC is much better ON than OFF for certain types of games, in my experience, since jitter (from non-VRR) can be more annoying to me. The way GSYNC fixes jittering more than exceeds the flicker disadvantage, as long as the game is very VRR

One problem when capping lower frame rates (e.g. 60fps) is the rapid entry/exit of LFC can be individual flicker events. LFC typically occurs at ~48Hz, but sometimes triggers on/off even if you're doing 60fps. In this situation, making sure the framerate never falls below 60fps, is key.

One method is to use GSYNC for fullscreen exclusive games only, and configure it on a per-game basis (global GSYNC turned off, but GSYNC turned on a per-game basis). There's way to use NVCP to use a whitelisting approach, where GSYNC is only enabled only when you run certain games.

The NVCP "whitelist approach" for GSYNC where it's off by default except for certain games:
  1. Monitor -> Adaptive Sync -> ON
  2. NVCP -> Set up G-SYNC -> ON only for fullscreen
  3. NVCP -> Manage 3D Settings -> Global Settings -> Monitor Technology -> Fixed Refresh
  4. NVCP -> Manage 3D Settings -> Program Settings -> Choose game to whitelist -> Monitor Technology -> G-SYNC
  5. NVCP -> Manage 3D Settings -> Program Settings -> Choose game to whitelist -> Vertical Sync -> ON
  6. NVCP -> Manage 3D Settings -> Program Settings -> Choose game to whitelist -> Max Frame Rate -> 235 (or use RTSS)
  7. Game Settings -> VSYNC -> OFF
NVCP per-game setting - GSYNC ON only for most co-operative games.

In this situation, G-SYNC is always disabled except for specific games. You can use VSYNC OFF for things like CS:GO/Overwatch, but G-SYNC for games like System Shock that performs better with OLED VRR ON.

Also, OLED VRR flicker is from the framerate yo-yo effect -- sudden halvings or triplings of frame rates. Like when bringing up menu or when a game is loading/shader compiling/texturestreaming. This is one of the main causes of VRR flicker problems on any LCD/OLED that is subject to VRR flicker (even some of my LCDs have a slight VRR flicker effect during large framerate yoyo effects). Another reasion is rapid exit/entry of LFC mode (where drivers' framerate suddenly doubles to prevent refresh cycles from falling below min VRR Hz range). So even if you have 60fps, you're already dangerously close single frames being 48fps, it may mean some frametimes are 1/40sec and other frametimes 1/80sec, to average 1/60sec. A single frametime into LFC territory, thus, can be a minor flicker event, especially if you love doing "RTX ON" and Ultra settings, which can often cause a single-frametime dip into LFC territory -- one too-slow refresh cycle will often create flicker event as it suddenly transitions into LFC vs non-LFC mode. Also, many graphics drivers will pre-emptively enter LFC mode a bit 'early' (this is annoying). Some people resort to range-editing the VRR range in ToastyX CRU to mitigate this, but this does not always work for all games.

The key to avoiding flicker events is avoiding too-slow frametimes (making sure no frametimes spike above ~10ms), which means you have to fiddle with the game settings to keep frame rates in the triple digits.

Re: Monitor Corsair XENEON 27QHD240 - G-SYNC flickering

Posted: 20 Jun 2023, 19:52
by jorimt
Horog wrote:
20 Jun 2023, 18:34
I was interested in the opinion of how you would proceed if there was no G-SYNC and 240 FPS and you would not be able to achieve more. So that the gaming experience is as good as possible. That's all. I don't have any particular preference. I play competitive games like Overwatch 2, but also a big MMORPG.
If you can tolerate tearing artifacts (which are less apparent at 240Hz), G-SYNC off + V-SYNC off + uncapped FPS, because unlike G-SYNC, standalone V-SYNC will cause latency and recurring stutter due to repeated frames if you can't keep your framerate above the refresh rate.

Again though, there's no "one" answer if you can't use VRR for tearing prevention with variable framerates; it's a series of trade-offs based on personal preference, system capability, and individual game performance.

Re: Monitor Corsair XENEON 27QHD240 - G-SYNC flickering

Posted: 21 Jun 2023, 21:22
by Horog
Chief Blur Buster wrote:
20 Jun 2023, 19:26
The key to avoiding flicker events is avoiding too-slow frametimes (making sure no frametimes spike above ~10ms), which means you have to fiddle with the game settings to keep frame rates in the triple digits.
Thank you for the explanation and tips. I tried to follow your last sentence. In the game Overwatch 2 I have, in a dark scene, without FPS limit ~205 FPS. If I set the FPS limit to 144 (with the help of RTSS) I will reach this FPS value stably anywhere in the game. See attached videos with chart.

Even still, the game flickers .... I have to state that this feature is terribly distracting for me. And if I'm playing, for example, Assassin's Creed and I'm somewhere in a dark tomb where it's almost 100% dark, it's extra unpleasant.

Thank you again for the help and guidance. I decided to operate the monitor without G-SYNC, even though it is absurd considering its price and the fact that I wanted to use G-SYNC when my HW cannot maintain 240+ FPS.

Without FPS limit
phpBB [video]


144 FPS limit
phpBB [video]


jorimt wrote:
20 Jun 2023, 19:52
If you can tolerate tearing artifacts (which are less apparent at 240Hz), G-SYNC off + V-SYNC off + uncapped FPS, because unlike G-SYNC, standalone V-SYNC will cause latency and recurring stutter due to repeated frames if you can't keep your framerate above the refresh rate.
Thank you for your help.