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

[peterQ95T]

First test of QN90A https://www.youtube.com/watch?v=cG_alkREmuo

And im NOT impressed at all wow stille DSE and Blooming worse then Q90 series

@PeterHu Its better you choose a LG or Sony Oled 2021

[peterQ95T]

Yes @RouDeR and the new 2021 lineup NEO Qled is nothing that i got impressed about still problems with DSE and blooming even worse than 2020 Qled.

https://www.youtube.com/watch?v=cG_alkREmuo

[PeterHu]

Haha, funny enough, yesterday I bought a 65" LG CX 100€ less than the 65Q90T was... it arrives on Friday and I'll have two weeks to decide. I'm not worried about burn-in because of our usage, but the living room is very bright (curtains are on the way) and I'm more worried of the reflections. If I have to move the dark blinds every time during the day to watch the TV, then I don't know. I've seen recently the early review units of Neo Qled got a big software update, and it might solve the blooming issues (DSE and other panel problems are different story though) and Rtings Suggestion site shows they are already testing the QN85A. So I hope CX will be enough good for our usage (I know the picture quality will blow away), but I'll keep my eyes open for the Samsung reviews for the next two weeks in case if we decide to return.

But to be honest, OLED is cheaper than the top LCD at the moment and  they are night and day. The new Neo Qled will be still expensive for at least half year so I guess at the moment CX is the best buy as long as the stores have it - C1 won't worth the extra money probably, G1 will be great but 3000€+ for 65”. My brother has CX and it got better with updates, LG fixed their own update bug in few weeks, kudos for that.

[SidL]

Could someone tell me which image mode has less input lag? Filmaker, Natural ...? Because in GAME MODE with that shameful local dimming is impossible!

[Galaxy_Echo]

Movie mode is the most suitable mode for gaming since it's the only mode that PWM is high enough. High frequency PWM isn't only eases eye strain but also decreases motion duplication. Besides, local dimming is functional correctly in Movie mode.

The disadvantage of gaming in Movie mode is not input lag, but loss of HGiG. No HGiG means PS5's build-in HDR calibration and picture quality are polluted by TV's dynamic tone mapping.

[MrDanteZ]

I think they fixed the dimming bug in the new update 1497. Can anyone confirm this as well?

[Iskandarkebab]

For me it was fixed 2 updates ago. Never happened ever again.

[Galaxy_Echo]

According to user report, the 1497 firmware seems to have fixed dimming bug.

[Meccs]

The 2019 models have the same issue. I hope they don't just fix it on the 2020 models....

[mrtoad883]

Yup. Mine does it too on the Q70R 2019 model. current version 1374.