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

[Biggydaklaus]

You can reproduce the local dimming bug also in PC mode if you watch a movie in fullscreen (youtube). When you exit the video and switch for example to a forum tab like this 6 min later the bug occurs. It not only in local dimming "high", its also in "standard/normal".

[Baron-Von-D]

I have the same problem on my 65q80t it was deriving me crazy.

hopefully they r going to fix this problem soon.

this tv has lots of problems 

[Jaggers]

Yep i have the exact same tv and problem. I believe they will deliver. Not going to pay 900€ more for lg cx.

[RouDeR]

Great news guys, 
Nvidia Released driver 457.09
which solved the issues with RTX 3000 series and the Samsung Qled TVs with VRR (at least it solved for my Q800T)
G-sync is now working in  4k@120hz !!!!!!!

[TomasTSH]

Good to know 👍

[daparky]

Have you got any videos

[RouDeR]

I`ll try to make a VRR related video today/tmrw and will post it here,
Sadly not everything is great because the VRR engages Pixel overdrive which causes some other issues.

[daparky]

What issues are you having?

[Masq]

Giving up on Samsung. Paid nearly $3000 for a Q8FN 2 years ago (which replaced a Samsung KS8000 that died after 2 years)... nothing but problems. Went through multiple panels with various issues from Nov ‘18 - May ‘19.
 Samsung did get me a semi-acceptable one eventually (after threatening a lawsuit), but even this one still has really bad DSE and gray bars.

Ended up buying another TV in Jun ‘19 because I was so disgusted, Sony X900F for my Game Room. That’s been my primary gaming TV since. No weird issues, no DSE, no gray bars, and $1000 less than the Q8FN. Granted, it’s a lower tier TV. 

So this week I start using the Q8FN again in anticipation of the PS5 & Series X, which will be set-up in my living room. Had almost forgotten about their garbage firmware that completely destroyed Game Mode. Lower backlight output, broken Local Dimming, HDR in Game mode is garbage. 

My guess is that they purposely do downgrades w/firmware “updates” because they think people are willing to buy new TVs every 1-2 years like cell phones now. Disgusting.

So I’m sitting here researching which TV to replace the the Q8FN with, finally wash my hands of it.

early options are LG CX and Sony X900H

Leaning towards the Sony

/end rant

[Norradach]

I have dimming problems on 85q950ts

fw 1402.7 pic mode hdr standard

It has problem in 4k bluray hdr movie and netflix 4k hdr 

i exchange new one but still have this problem

https://youtu.be/c4eXY1Z3uUk