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

[SidL]

Alleluia! That's what I'm talking about! and people just close their eyes and ignore this SERIOUS problem with this TV. I hadn't taken a picture because my smartphone doesn't have a good camera. I bought this TV that costs a lot of money precisely because of the local dimming and in the main mode for me that the game mode does not work! Local dimming only gets a little better in game mode if GMP is ON, but GMP ON is very bad, the image loses some quality and is full of artifacts on the screen and ghosts. This problem came with the 1304 update.

[jayh89]

I'd suggest a new thread for local dimming... make it stand out more.

[BogaMoge]

Edit : repeat of a previous post... sorry

[BogaMoge]

Done.

Q95T/90T : Local Dİmming not functional in Game Mode

Feel free to contribute so the thread gets bigger...

Edit : link didn't work, should work now...

[Suriya]

https://eu.community.samsung.com/t5/tv/v1304-0-update-downgraded-game-mode-on-q95t-without-local/m-p...

Few weeks back i opened this topic 

[brook1]

I don’t get it guys y’all are so confusing did they fix the issues (including the local dimming on game mode without gmp) with the 1402 update or not ?? I tried to understand what you guys are saying but none make sense all i see complaining without mentioning what the update fixed or if it fixed anything at all. I want a clear answer if someone has it did they fix something with this update or not ?

[TomasTSH]

Dimming bug which would dim the whole picture every 6min in Game mode has been fixed. What they're complaining about is that Local Dimming doesn't work as well in game mode as it does in movie mode. But that's exactly how that's supposed to be to have low input lag. Some are saying Samsung should sacricife some low input lag for better local dimming in game mode. Well just play in movie mode then, good local dimming with worse input lag.

[brook1]

Thanks for answering. You have a point there i mean why would local dimming matter over input lag while playing competitve games ! However you can switch the game mode off to enjoy the full local dimming experience with other story type games since input lag wouldn’t be that important. People really love to complain over weird things seeing some replies here makes you feel like we’re facing a disaster it’s not that deep. The most important part is the dimming bug that’s all, how do you want 10ms input lag without sacrificing some features ! 

[BogaMoge]

You'd be perfectly right... IF I didn't get full purple ghosting in any mode other than Game Mode!!!

So that makes my options :

- Game Mode : bad local dimming and weird horizontal "scanlines"

- Other Modes : purple ghosting in dark scenes

So more or less any game that is even a bit dark is not really playable for me right now, a shame for a flagship tv...

[brook1]

You should consider exchanging it then and see if the problem still exists since i don’t think this is a general issue for all panels. Did you face this issue after the new update 1402 ?