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

[LCDeez]

The real problem as I see it is this: 

When the PS5 comes out and you can run it through native 120hz (yeah, I’m not saying games will hit this target but you’ll be able to select it to output), and with VRR engaged, the dimming will be TV ruining. I could see a class action easily if this isn’t fixed by then. 

You cannot have game motion on with VRR, so the dimming will be highlighted, if anyone can confirm it happens under these circumstances.

[max0x7ba]

Same issue on my Q95T in any mode with local dimming other then low.

However, I use low local dimming in all modes, anything above it does too much brightness and contrast, which destroys the scene atmosphere and is too much, and makes text look weird, IMO. 

[RiotRMD]

Hi all,

I swear I have only started seeing this in the past three days. I've owned the tv for 3 weeks. Ever since I got it, I've had firmware 1302, but manually updated to 1304 today via a download from Samsung Europe's site.  American site seems to have 1301.5. (I love how they have no "patch notes", its ironic, I write those at work and tend to keep them short )

Is this "Inverse Ghosting?" I havent seen this happen up until a few days ago and it's driving me crazy since I'm sure it wasn't there before.

[Richierich99]

I have the UK Samsung q85t 65inch model. 

Firmwure 1302 latest I believe.

HDR game mode I can confirm my screen does not go dim! Using ps4 pro

Although my screen I think dosent go as bright (example) as my ks8000 went alot brighter!

I thought these qleds were brighter, but I guess that's another thread I shall be doing soon!

And yes my q85t gets quite hot! 

[smp79]

That's not a software issue - it's just a slow LCD panel.

[LCDeez]

Did you turn game motion off with dimming at standard or high? 

[Suriya]

I'm 100% sure you're wrong. First turn off game motion plus then trigger any game with HDR in game-mode keep static content(to identify clearly) on screen for 10min you'll see the brigthness drop by 40%.

Wondering why you came here if the dimming didn't happen?

[RiotRMD]

You mean the ghosting? The issue with that is that I didnt have that a week ago and the firmware is the same, so that's what is bugging me.

[max0x7ba]

Also, in Game mode, Sharpness 9 is the neutral, Sharpness 0 adds blur. See https://eu.community.samsung.com/t5/tv/game-mode-sharpness-9-is-the-neutral-on-q95t/m-p/1945549

[Brycekent]

Anyone know the pwm default value for the q80t on the service menu? Thanks