Blur Busters Forums

Posted: **07 Dec 2022, 18:46**

Hi All,

I recently picked up a 55 inch LG QNED85 for my flight sim hobby, I read the info on setting up G-SYNC on this TV. It is a Freesync Premium TV but when I open the gaming menu on the TV it shows that NVIDIA G-SYNC is active. If I set the refresh rate to 120Hz G-SYNC works perfectly but I am getting a horrible screen flickering. My FPS rate varies between mid 40's - Mid 60's and generally sits around 60 so I use Riva to cap the fps @ 60 and it is very smooth.

If I change the refresh rate to 60Hz (Which makes more sense seeing my fps are around 60) with G-SYNC active the flickering is not present but although G-SYNC shows as being active both on the TV's game menu and from the NVIDIA control panel if my fps drop from 60 to even 50 - 55 it is just not smooth like it is at 120Hz. I cannot for the life of me stop the screen flickering and cannot figure out why at 60Hz G-SYNC doesn't seem to work. The VRR range on this TV is 24Hz - 120Hz so I am always well above the lower end.

If anyone can offer any advice as to how to either stop the flickering at 120Hz or have G-SYNC work at 60Hz I would really love to hear your thoughts. I do have a 30 day return window, I really like the picture quality of the TV but if I can't use G-SYNC I may as well return it and get something cheaper that doesn't have this technology.

Posted: **07 Dec 2022, 20:49**

Richdem wrote: ↑
07 Dec 2022, 18:46
If I set the refresh rate to 120Hz G-SYNC works perfectly but I am getting a horrible screen flickering.

Can you expound on the type of flicker you're seeing?

Because on the step down model (I couldn't find a technical review for the 85), it may not be related to G-SYNC at all, but instead due to the fact that the display may use pulse width modulation (PWM) to control brightness. I.E. it wouldn't be a flicker-free display like most other modern high refresh rate models are.

According to RTING's review:
https://www.rtings.com/tv/reviews/lg/qned80

The LG QNED80 uses pulse width modulation (PWM) to dim its backlight at all brightness levels. The flicker depends on the picture mode you use, and you can see the differences below. The 120Hz flicker can be noticeable and cause image duplication with 60 fps signals, like when you're gaming as it flickers at 120Hz in Game Mode.

Picture modes with 480Hz flicker:

Expert (Dark space, night)
Expert (Bright space, daytime)
Cinema
FILMMAKER MODE

Picture modes with 120Hz flicker:

Vivid
Standard
APS
Sports
Game Optimizer
All HDR modes

You could try a picture mode that uses 480Hz PWM to see if that alleviates the flicker, if you haven't already. Again though, it's not the identical model, so it may or may not apply in your case.

Richdem wrote: ↑
07 Dec 2022, 18:46
If I change the refresh rate to 60Hz (Which makes more sense seeing my fps are around 60)

For future reference, lowering the physical refresh rate when using G-SYNC slows overall frame delivery, regardless of framerate, and is not recommended.

1) 60 FPS G-SYNC at 120Hz refreshes 60 times per second, but each frame is scanned in at 8.3ms per, whereas 60 FPS G-SYNC at 60Hz refreshes 60 times per second, but each frame is scanned in at a much slower 16.6ms per, and 2) now that the max physical refresh rate is only 60Hz, the max G-SYNC range is now also 60 FPS, which means you need to limit the framerate to ~57 FPS to account for frametime variances to keep G-SYNC active.

Richdem wrote: ↑
07 Dec 2022, 18:46
The VRR range on this TV is 24Hz - 120Hz so I am always well above the lower end.

As mentioned above, VRR range is dependent on what physical refresh rate you currently have the display set to. At 60Hz, the high-end of the VRR range would max out at 60. What the low end would be on that particular display when set to a non-native/maxed physical refresh rate I can't say (depends on the TV model).

Posted: **08 Dec 2022, 08:06**

jorimt wrote: ↑
07 Dec 2022, 20:49

Richdem wrote: ↑
07 Dec 2022, 18:46
If I set the refresh rate to 120Hz G-SYNC works perfectly but I am getting a horrible screen flickering.
Can you expound on the type of flicker you're seeing?

Because on the step down model (I couldn't find a technical review for the 85), it may not be related to G-SYNC at all, but instead due to the fact that the display may use pulse width modulation (PWM) to control brightness. I.E. it wouldn't be a flicker-free display like most other modern high refresh rate models are.

According to RTING's review:
https://www.rtings.com/tv/reviews/lg/qned80
The LG QNED80 uses pulse width modulation (PWM) to dim its backlight at all brightness levels. The flicker depends on the picture mode you use, and you can see the differences below. The 120Hz flicker can be noticeable and cause image duplication with 60 fps signals, like when you're gaming as it flickers at 120Hz in Game Mode.

Picture modes with 480Hz flicker:

Expert (Dark space, night)
Expert (Bright space, daytime)
Cinema
FILMMAKER MODE

Picture modes with 120Hz flicker:

Vivid
Standard
APS
Sports
Game Optimizer
All HDR modes
You could try a picture mode that uses 480Hz PWM to see if that alleviates the flicker, if you haven't already. Again though, it's not the identical model, so it may or may not apply in your case.

Richdem wrote: ↑
07 Dec 2022, 18:46
If I change the refresh rate to 60Hz (Which makes more sense seeing my fps are around 60)
For future reference, lowering the physical refresh rate when using G-SYNC slows overall frame delivery, regardless of framerate, and is not recommended.

1) 60 FPS G-SYNC at 120Hz refreshes 60 times per second, but each frame is scanned in at 8.3ms per, whereas 60 FPS G-SYNC at 60Hz refreshes 60 times per second, but each frame is scanned in at a much slower 16.6ms per, and 2) now that the max physical refresh rate is only 60Hz, the max G-SYNC range is now also 60 FPS, which means you need to limit the framerate to ~57 FPS to account for frametime variances to keep G-SYNC active.

Richdem wrote: ↑
07 Dec 2022, 18:46
The VRR range on this TV is 24Hz - 120Hz so I am always well above the lower end.
As mentioned above, VRR range is dependent on what physical refresh rate you currently have the display set to. At 60Hz, the high-end of the VRR range would max out at 60. What the low end would be on that particular display when set to a non-native/maxed physical refresh rate I can't say (depends on the TV model).

Thank you for the excellent response,

I couldn't find too much technical info on this TV either, I will definitely try one of the other picture frames you mentioned. Now I understand why G-SYNC didn't seem to be working properly at 60Hz. If I set the refresh rate to 120Hz is it ok to cap the frames to 60 with Riva? I find this gives me the best frame time and also keeps my RTX 3090 from running at full tilt all the time as it would if I just leave the frame rate uncapped.

Posted: **08 Dec 2022, 08:52**

Richdem wrote: ↑
08 Dec 2022, 08:06
I couldn't find too much technical info on this TV either, I will definitely try one of the other picture frames you mentioned.

Yeah, I couldn't find much technical info on the 85 model myself, so no guarantee it has the same characteristics as the 80, but worth trying the different picture modes to see if it applies the same regardless.

If it's not that, then the only other common factor that could cause flicker where software-level LCD display VRR is concerned is the LFC (low framerate compensation) threshold potentially being set too low out-of-box, at which point you'd need to manually inspect and adjust the VRR range with a tool like CRU, but doing so varies by display, so instructions specific to each model can't really be provided.

Richdem wrote: ↑
08 Dec 2022, 08:06
Now I understand why G-SYNC didn't seem to be working properly at 60Hz.

Right; current max refresh rate determines working VRR range.

Richdem wrote: ↑
08 Dec 2022, 08:06
If I set the refresh rate to 120Hz is it ok to cap the frames to 60 with Riva?

Yes, at 120Hz on your display, working VRR range should approximately be 20-120, so any framerate limit set within said range is perfectly acceptable; G-SYNC will simply refresh the display how ever many times per second the current framerate is (so long as it is within the currently set physical refresh rate/VRR range).

Posted: **08 Dec 2022, 12:37**

jorimt wrote: ↑
08 Dec 2022, 08:52

Richdem wrote: ↑
08 Dec 2022, 08:06
I couldn't find too much technical info on this TV either, I will definitely try one of the other picture frames you mentioned.
Yeah, I couldn't find much technical info on the 85 model myself, so no guarantee it has the same characteristics as the 80, but worth trying the different picture modes to see if it applies the same regardless.

If it's not that, then the only other common factor that could cause flicker where software-level LCD display VRR is concerned is the LFC (low framerate compensation) threshold potentially being set too low out-of-box, at which point you'd need to manually inspect and adjust the VRR range with a tool like CRU, but doing so varies by display, so instructions specific to each model can't really be provided.

Richdem wrote: ↑
08 Dec 2022, 08:06
Now I understand why G-SYNC didn't seem to be working properly at 60Hz.
Right; current max refresh rate determines working VRR range.

Richdem wrote: ↑
08 Dec 2022, 08:06
If I set the refresh rate to 120Hz is it ok to cap the frames to 60 with Riva?
Yes, at 120Hz on your display, working VRR range should approximately be 20-120, so any framerate limit set within said range is perfectly acceptable; G-SYNC will simply refresh the display how ever many times per second the current framerate is (so long as it is within the currently set physical refresh rate/VRR range).

I spent the morning trying the different things you suggested and nothing worked unfortunately, I do have CRU and by default it was showing the VRR range to be 24Hz - 120Hz. I did change it to 45Hz - 120Hz and there was a small improvement but the fans on my RTX 3090 were running pretty maxed out even though the load was not at 100%. I guess ultimately I will be returning this TV and looking for a different option.

Do you have any models you can suggest I take a look at where G-SYNC does work? I know G-SYNC compatible displays can have their limitations but I only use it for one purpose which is my flight simulator and with my PC I can usually maintain 60fps with occasional dips to the 45 - 50 range so I don't need a display that has full G-SYNC hardware (although I do not know if a TV with this actually exists)

Appreciate your help, you gave me some great things to try.

Posted: **08 Dec 2022, 14:25**

Richdem wrote: ↑
08 Dec 2022, 12:37
Do you have any models you can suggest I take a look at where G-SYNC does work? I know G-SYNC compatible displays can have their limitations but I only use it for one purpose which is my flight simulator and with my PC I can usually maintain 60fps with occasional dips to the 45 - 50 range so I don't need a display that has full G-SYNC hardware (although I do not know if a TV with this actually exists)

The only way to virtually "guarantee" flicker-free G-SYNC operation is to buy a monitor containing a hardware module, which no mainstream TV models (that I know of) currently feature (only very expensive "G-SYNC Ultimate" "TVs:" see this official list and sort by "Size": https://www.nvidia.com/en-us/geforce/pr ... ors/specs/).

Both LCD and OLED VRR-capable TVs can have VRR flicker in different scenarios from different causes, and while many FreeSync G-SYNC Compatible (aka software-level VRR) gaming monitors don't have an issue with VRR flicker, others can; it varies by model.

So the only thing I can suggest is to read any technical reviews available on the VRR-capable TV models you're looking into, as well as skim/search owners threads on AVS Forums and elsewhere.

I'd ask if you've considered a VR headset like the Reverb G2 to replace a monitor, but even with a 3090 in a game like, say, MSFS, you'll be getting as low or lower performance than on a 4k TV, and that's assuming you don't suffer from motion sickness.

That all said, as I originally asked, what "type" of flicker are you experiencing? Constant subtle brightness fluctuation, intermittent blackouts, etc? May help to narrow it down.

Posted: **08 Dec 2022, 23:42**

jorimt wrote: ↑
08 Dec 2022, 14:25

Richdem wrote: ↑
08 Dec 2022, 12:37
Do you have any models you can suggest I take a look at where G-SYNC does work? I know G-SYNC compatible displays can have their limitations but I only use it for one purpose which is my flight simulator and with my PC I can usually maintain 60fps with occasional dips to the 45 - 50 range so I don't need a display that has full G-SYNC hardware (although I do not know if a TV with this actually exists)
The only way to virtually "guarantee" flicker-free G-SYNC operation is to buy a monitor containing a hardware module, which no mainstream TV models (that I know of) currently feature (only very expensive "G-SYNC Ultimate" "TVs:" see this official list and sort by "Size": https://www.nvidia.com/en-us/geforce/pr ... ors/specs/).

Both LCD and OLED VRR-capable TVs can have VRR flicker in different scenarios from different causes, and while many FreeSync G-SYNC Compatible (aka software-level VRR) gaming monitors don't have an issue with VRR flicker, others can; it varies by model.

So the only thing I can suggest is to read any technical reviews available on the VRR-capable TV models you're looking into, as well as skim/search owners threads on AVS Forums and elsewhere.

I'd ask if you've considered a VR headset like the Reverb G2 to replace a monitor, but even with a 3090 in a game like, say, MSFS, you'll be getting as low or lower performance than on a 4k TV, and that's assuming you don't suffer from motion sickness.

That all said, as I originally asked, what "type" of flicker are you experiencing? Constant subtle brightness fluctuation, intermittent blackouts, etc? May help to narrow it down.

I’m so sorry, I just realized I didn’t answer your question about the type of flicker. It’s basically the brightness of the screen varying for split seconds causing the entire screen to flash momentarily. It only happens at 120Hz with G-SYNC enabled. I’ve always strived to achieve a flat frame time graph so the frame timing is as even as possible. Even with perfect frame timing it’s still flashing.

Posted: **09 Dec 2022, 12:31**

Richdem wrote: ↑
08 Dec 2022, 23:42
It’s basically the brightness of the screen varying for split seconds causing the entire screen to flash momentarily. It only happens at 120Hz with G-SYNC enabled. I’ve always strived to achieve a flat frame time graph so the frame timing is as even as possible. Even with perfect frame timing it’s still flashing.

I notice the QNED85 has a FALD backlight; have you ruled out local dimming by disabling it when G-SYNC is enabled? It's possible the flicker is caused, at least in part, by local dimming not being optimally timed to VRR operation.

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