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

[Peto Pedro]

That's defo faulty unit go back where u purchased it from and get replacement or refund 

After 10 seconds no one tv does such thing but gradually 

[kaveh serousheh]

@peter: Nice..! enjoy it! 🤘🏽🤘🏽 4K 60hz is not that HORRIBLE (omg, omg!!) as you intend to it is 😉 most of games are in 60 hz as i’m sure you know it aswell. i prefer games in 60 hz and sports games in 120. my setup is 4k 120hz with game mode off as like you said samsung tv in hdr is really bad. i choosed 120 hz just because of using the full bandwidth (40gb/s) ”hdmi 2.1 ish” 

[Peto Pedro]

You can't have 4k120 when game mode off then it will fall back to 4k60 u need to enable game in order to have 4k120hz.. And then u need to enable either g-sync or free-sync to have vrr.. I play warzone and I have 75 80fps but I will be upgrading to 3060 or 3070 rtx so will have nice full 100 or 120 fps

[SidL]

It's a shame that sony stopped selling TVs in my country 😐

[peterQ95T]

Really what a shame. I got rid of my Q95T and bought a Sony X95J and im so happy with that TV. I will never go back to Samsung faulty tvs.

[Ulysses31]

Noticed this happening to my 85" Q950T with last couple of firmwares.

However it seems to happen when the room is warmer than usual in my case. Today's a colder day in my country and my TV room's a lot cooler  and I didn't notice a sudden drop in brightness during the hours I used it as a PC monitor.

So it might be the ABL kicking in to stop overheating in warm/hot rooms.

[Peto Pedro]

What was wrong with Q95T ?

[Ulysses31]

If you're asking why I picked the Q950T over the Q95T it's because it has more dimming zones.

[Peto Pedro]

No u said u bought Sony 

[Ulysses31]

You must be confusing me with someone else. I don't have any Sony TVs. The Q950T(S) is the 2020 QLED 8K TV from Samsung.