2020 QLED T models (Q80T, Q90T, Q800T, Q900T) HDR game mode brightness / local dimming bug

[Rauttis]

I bought a Q80T a couple of days ago and have noticed a really annoying issue when using the tv with the combination of HDR and game mode.

I'm fairly certain this is a software bug in the TV since I can reproduce this issue with 100% accuracy, and it happens on the dot at the same moment every time. It's basically on a timer.

Basically when the game is displaying a HDR signal and game mode is enabled, exactly after 6 minutes the brightness of the TV suddenly drops by around 20 (50 -> 30). The value of brightness setting doesn't actually change however. Messing with the brightness setting does not restore the brightness to it's original state, but changing the local dimming setting from standard to low and then back to standard does. Switching game mode off and then back on also fixes the issue, but then it happens again EXACTLY after 6 minutes (I've timed this with a stopwatch).

Has anyone else experienced this issue? Or can someone maybe test this on their TV to see if you can reproduce it?

Exact repro steps on how I can reproduce this 100% of the time on the PS4 Pro:

1. Set brightness to max (50)
2. Set local dimming to standard (bug happens on high as well)
3. Enable game mode
4. Turn off game motion plus
5. Turn off intelligent mode and all the brightness related settings in eco settings, as these can influence the brightness level of the tv.
6. Launch a game that runs in HDR
7. Start your stopwatch
8. Do whatever you want in the game or you can also go back to PS4 menus, find a bright scene where you can notice a brightness drop easily
9. When the stopwatch hits 6 minutes, you should see the TVs brightness suddenly drop by a large amount. By eye the brightness drop seems about equal to dropping the brightness from 50 -> 30 by hand.
10. Go to picture settings and set local dimming to low (brightness does not change)
11. Set local dimming back to standard (brightness suddenly jumps to the original level. Brightness can be restored by switching input away and back as well, or by disabling and re-enabling game mode)
12. And again after EXACTLY 6 minutes the bug again repeats and the brightness drops down again

Some other notes: The PS4 has a screensaver that basically dims the screen if it is idle for a while. This is not the cause of this, this happens even when the console is in active use and the brightness can be restored temporarily by changing the local dimming setting like described above. I have not managed to reproduce this issue with game mode off, so it seems to be related to game mode.

Software version: 1304

[Suriya]

Pls check when it's happens second time in hdr. And sdr sometimes it's happened sometimes not. Weird

[LCDeez]

All I can say to you is: the dimming always happens. Doesn't matter if it's every 6 minutes or completely random. 

[Suriya]

Today i have triple checked its happening every 6min exactly again and again in HDR game mode.

Dimming is clearly noticeable when displaying HDR mid dark area
(EX: Last of us 2 main menu "the boat in river")

Sometimes hard to identify when displaying HDR Brighter areas.

[Hedo]

Hello all. First of all, it's beyond inexcusable that Samsung has been absent from these posts with any info or assurance this issue would be addressed.

A little background: I work at a network as a Colorist for scripted prgrams and master them in HDR 10 and Dolby vision. 10 days ago we purchased the Q80T, and I found that this darkness/dimming issue was prevelant in ALL HDR content. It was maddening to see the image slowly go dark. We were hours away from returning this TV, until I stumbled upon what appears to be the solution. 

Start a program you know is in HDR. Go to Picture Mode and use the Dynamic setting ( you should see a small HDR icon visible in the setting). Set the color to standard, as cool is too blue, which is not cool. You can press up on your remote while on the Dynamic setting and adjust your contrast, brightness, etc, to where you like it. I leave the Pic Clarity setting off. I've played through several programs on Netflix, Disney and Prime, and they stay rock solid now. Also, once you change these settings, they remain saved so you don't have to do this every time. For other content, just use whatever Pic setting works for you. Let me know how it works! I for one am satisfied and won't return it now. 

In any case, let's get with it. Samsung! You need to address this and roll out an update STAT! 

[GabrielGon]

That's excellent news!! Fananlly. Can someone confirm this? (I'm still waiting for a price drop on the Q95T in my country).

But, this is not a solution for game mode, right?

[jayh89]

This "fix" does nothing for me when it's game mode that I want to use. Maybe it'll fix it for some people though! 

[Luke_H]

Yeah I agree, if anything I notice it way more during game mode on.

sort it Samsung!!!!

[AlexPi314]

Doesn't this simply mean that the TV is overheating and applying thermal mitigations, one of which is to reduce the screen's brightness?

It would make sense that this happens in game mode and HDR most often as those are the most taxing modes, and less often in SDR.

If true, good luck getting Samsung to admit that their TV is overheating under normal operating conditions.

[KindOldRaven]

Not a solution for me. In Dynamic mode the TV has a PWM rate of around 120hz which causes me and my girlfriend to have a little bit of a headacher after a while, currently only Movie mode and Game Mode have a PWM rate of 960hz (yes, I've tested this and so has Rtings; their review just isn't updated since they think it might be a bug lol) and thus are almost ''pwm-free''. 

So unfortunately changing to dynamic will not offer a solution here.

[LCDeez]

What about setting game mode dimming to low?