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

[lmpcardoso]

Just don't buy, the 2020 Qled series all have serious issues like the local dimming, ghosting, purple ghosting, and they are taking too long to address all this issues.

Last year models have common problems and even today they are not solved. 

Shame Samsung... 

[brook1]

After the latest firmware the picture quality in game mode is far better than it was but the local dimming is acting weird the response of the dimming zones isn't instant you can see how it changes and it takes time i hope they can still maintain its effectiveness but work on the response also i got the scanlines issue after the update, in game mode with gmp off only especially in the grey and red colors you can actually see the lines go from bottom to the top. Still hundred times better than the washed out picture quality we used to before the firmware

[Budolf]

The only problem I am having with firmware 1403.1 is the scanlines in game mode with GMP off. That wasn’t there before. That sucks but other than that this q90T is great!

[Baron-Von-D]

try playing with the contrast enhancer i think it would go away if u switch it off . check this video out

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

im having the same problem and its driving me crazy on battlefield on ps4 pro

[Parameter]

They weren't there before?? Is this with VRR on?

Interesting to know that they only started appearing with the newer firmware, maybe a bit of hope a firmware update can sort this whole VRR scan line issue out

[cragcrag]

I can't update from 1403 to 1403.1.

Doing it via USB and it says "no update is available" when searching the USB and I imagine it's because the TV is just seeing the 1403 and not the .1 part.  

Really frustrating. And yes, I'm doing it correctly, I've done it correctly before to get to 1403 in the first place.

Anyone else having this issue?

[Budolf]

Nope, came with 1403 firmware. Its in game mode with GMP off and i think its VRR by default then. I had ghosting with that setting with previus firmware 11.. something and they fixed that. So I think both issues are solvable.

[jexx]

I am dealing with this same issue with my new xbox series X. Samsung Q80T. I can't figure out the random dimming! There's no way to turn dimming off, only low. Might be it.

Additionally, I have to turn game mode OFF in order to play games. With game mode ON, the game looks terrible! Bad HDR! When we watch videos, we have to turn game mode ON, or the frame rate is terrible. It looks like bad soap opera quality.

So, we turn it ON to watch Netflix and OFF to play games. That's backwards right? And the quality with game mode ON leaves us stuck with that horrible HDR/too many filters look. It's insanely dark and hard to see. Blacks dont display correctly either.

lastly, default brightness and contrast are 50/50. What the heck? It comes with maxed out contrast and brightness? I can't control that?

[jexx]

Dealing with this exact same issue. It just automatically dims! Why!? I've disabled all features and absolutely CAN NOT USE GAME MODE. It looks absolutely TERRIBLE.

So I play with game mode off and the picture is good, but it auto dims white text, game menus, health bars, etc. EXTREMELY frustrating.

[Harmen0]

I bought the EU q80t tv last week, came installed with 1403.

I only encountered the 6 minutes dimming bug on one device: using my laptop on the HDMI 2.1 port using an HDMI 2.1 cable (my laptop, however, is not 4k, nor is it HDR). Using the same laptop on another port in game mode did not yield any issues for me.

For other devices I have used with zero local dimming issues:

-Series X on HDMI 2.1 port with stock Series X HMDI cable

-PS4pro on port 3 with high speed HDMI cable

-Nintendo Switch on port 2 with the stock Switch HDMI cable.

All look good and HDR is working bright and well on the Series X and Pro.

I do, however, have one major issue: the scrolling lines on the 4K resolution in game mode (Switch and laptop at 1080 do not have this issue, nor do the Pro and Series X when I change output to 1080p). I like to play dark horror games and in greyish areas it can be super visible. This really is unfortunate because other than this I am super happy with how games look on my end. I did not notice it in the first games I tested, but now there are several games where it is super visible in many instances.

I see several mentions in this thread, so is it true that this issue is relatively new due to an update (meaning it is likely a software thing)?

The lines are not present when turning on game motion plus so I have a question: how does this mode affect input lag when putting everything to zero? (essentially turning it off while having it activated, right?). Offcourse this means the lines are there for VRR or 120 fps, so this does not negate the issue either way.