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

[RouDeR]

Sometimes it turns itself off after 10-20 seconds, some times it remains with black screen and I have to turn it OFF  so I can have a picture again.

[Vagval13]

Which option are you referring to?

[Soccercrazy1]

I wanted to clear up some of the things I have said before. Keep in mind I have the US version. 

I have been saying that local dimming has greatly improved in the update compared to pre update. And it is true. I'm not imagining things. I posted pics and I'll post again here for reference. There is still blooming in gameode but I have said it is acceptable now. I don't get blue blacks in games now. I still get them in loading screens but they are way better. Also I no longer have the dimming bug.

I also use GMP now because local dimming is even better with it on. I use Warzone gunsmith screen to compare. The gears 5 load up screen (the one I'm going to post) is the best because the background is black where in cod it's just slightly over black. That is understandbly difficult to replicate if local dimming doesn't work properly. I know it's not pure black in warzone gunsmith screen because I had an OLED before. 

Now the difference between high and standard in local dimming with game mode on. You need to get a black screen with a logo or something like the gunsmith or gears loading screen. With GMP off, standard dims highlights in black areas to reduce blooming. High will not dim the highlights in dark areas so you end up with more blooming. With GMP on, standard works the same as it of for the most part but highlights in dark areas are slightly brighter and blacks are deeper. High with GMP is very good in certain scenes. The gears 5 logo looks incredibly bright with very deep blacks all around. It looks like game mode is almost off as to how good it looks there. However it has a problem. In the gunsmith screen in warzone, since the background is not pure black and you have those white dots that fly around, the whole screen is blue from bleeding due to the fact it's trying to push the highlights of the dots and gunto the max. 

I have set on GMP on with judder reduction at 1 to get some color back. (I don't know why that does that haha). I have local dimming set to standard for it's the best at controlling blooming.

These pics have local dimming set to standard in game mode with GMP off. Keep in mind with it on it is even better.

 Game mode HDR pre update

 Game mode HDR post update set to standard local dimming

 Game mode off

Please click on the pics to get a full view

 

[daparky]

Thanks for this.

I think the big issue now is HDMI 2.1 sources.

[ad1994]

Forgive me, what is HGIG? Also, RTings says use Contrast enhancer, would you recommended it to be off?

I'm trying to get the update now but it keeps saying an update isn't available. Is the only way via USB or can I force the update?

In terms of the update, is there a way to 

[Vagval13]

Hgig is an hdr standard that in a scene by scene basis tone maps hdr in order for it to fully utilize the capabilities of your screen. So in essence in laymans terms, the best that your particulat screen can offer in hdr, hgig will replicate in a scene by scene basis. It might give you at first the impression that it doesn't pop as much, but it is accurately rendering your hdr image, wereas before you might have had the impression of more pop but you mignt have had highlights that were clipped and you lost detail. You should always have it on i believe. 

[lmpcardoso]

Does anyone here have this problem wen turning off the GMP?

I have already updated to the new firmware and the problem is persists... 

ON

OFF

Thank you all.

[jayh89]

This issue isn’t fixable. I had to replace 2 q80t’s before I replaced it with the q85t (which didn’t have this issue). I’m led to believe that some q80t’s are broken... 

[AZGreg]

Can someone post a comprehensive list of the best settings when using game mode?

[lmpcardoso]

I cant believe this. I have paid more than 1200€ for one tv that on the paper was the best for me and in the end it has a bug non fixable? 

Samsung never again, i will try to return the tv but i have it by more than 2 months already.

This realy sucks...