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2020 QLED T models (Q80T, Q90T, Q800T, Q900T) HDR game mode brightness / local dimming bug

(Topic created on: 01-10-2020 06:36 PM)
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Rauttis
Explorer
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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

2,028 REPLIES 2,028
jdk2087
Pioneer
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Can anyone confirm or deny that the Q80/90 does 4K at 120hz? I’ve seen some people say that it doesn’t, but I thought rtings said that it probably could with HDMI 2.1. 

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jayh89
Helping Hand
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Do you have any proof Samsung said this? :smiling-face: I hope it’s true. 

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8bit
Explorer
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I followed the steps and it didn't work for me, had no valid install on my USB. Formatted the usb drive, moved the zipped folder to it, unzipped contents onto root, plugged into tv, clicked update now, searched usb drive for update, nothing came up. 

What did I miss?

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daparky
Pathfinder
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The manual states 4k @ 60hz with VRR enabled. The panel can do 4k @ 120hz, just not with VRR enabled.

 

Download the e-manual and search for FreeSync, you'll see a list of supported resolutions and refresh rates. This is as official as you can get with  confirmation, the manual.

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jayh89
Helping Hand
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Can someone explain what difference 60/120hz in VRR makes? Compare both for me? 

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jayh89
Helping Hand
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This link shows a very handy table. It shows that MOST TVs are 60Hz in VRR at 4K. https://www.rtings.com/tv/tests/motion/variable-refresh-rate

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Blewnote
First Poster
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Why do you say that Samsung turns off all image processing in game mode?  That sounds insane. 

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daparky
Pathfinder
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LG seems to have nailed it this year, they can do 4k/120 with VRR enabled.

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IamPeacock
Journeyman
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OK, I'm returning the TV tomorrow.

I really had no idea it's 4K/60 VRR and not 120.

 

I guess the only alternative is getting a CX then. But i'm afraid of burn-in.

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jayh89
Helping Hand
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Burn in is a serious worry with OLEDs but they're the only ones that do 120Hz. What difference does it make if it's 60 or 120? Genuine question as I'm not sure??

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