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

[PawelMerlin]

There can be difference in hardware between US and Europe. Samsung tends to give better hardware  for exactly the same models in US (for example in Galaxy S20). This would explain the time difference in updates. This TV will be very last Samsung's product I spent money for. I was saying the same when I was leaving Samsung's R&D but TV got me and I regret this.

[PawelMerlin]

Even rtrings says that Q80T in EU is worse:
"Note that the EU version of the Q80T is different. It doesn't have the ultra viewing angle layer, and it has a worse local dimming feature. "

https://www.rtings.com/tv/reviews/samsung/q80t-qled

[PawelMerlin]

As for the VRR refresh rate there are differences based on size of screen

Size	US	Canada	UK	Warehouse Variant	Refresh rate	FreeSync
49"	QN49Q80TAFXZC	QN49Q80TAFXZC	QE49Q80TATXXU	QN49Q8DTAFXZA	60Hz	No
50"	QN50Q80TAFXZC	-	-	-	60Hz	No
55"	QN55Q80TAFXZC	QN55Q80TAFXZC	QE55Q80TATXXU	QN55Q8DTAFXZA	120Hz	Yes
65"	QN65Q80TAFXZC	QN65Q80TAFXZC	QE65Q80TATXXU	QN65Q8DTAFXZA	120Hz	Yes
75"	QN75Q80TAFXZC	QN75Q80TAFXZC	QE75Q80TATXXU	QN75Q8DTAFXZA	120Hz	Yes
85"	QN85Q80TAFXZC	QN85Q80TAFXZC	QE85Q80TATXXU	QN85Q8DTAFXZA	120Hz	Yes

[8bit]

I can confirm that the "new" US update on Oct 5th did nothing for me, my TV did not detect a new update when I plugged the USB in.

[WackyHackster]

@8bit, thank you that is actually helpful. I'm from U.S. and I was wondering the same thing about the date changing to October.

[TomasTSH]

For me game mode works as expected, also using GMP on, mostly playing god of war with hdr on ps4 pro and see no issues. I had dimming issues watching movies in filmmaker and movie mode from PC where it dimmed after 6 mins, but playing games in game mode with GMP on is excellent and it looks pretty amazing. With GMP off the picture dims after 6 minutes but people are saying the new update fixes that. Can't confirm as I'm from UK and we still don't have the update yet. But for gaming this TV exceeded my expectations, very low input lag, the picture is amazing, the sound is great if you don't have a sound system. The local dimming is worse in game mode but still not bad, but again people are saying the new update improves that too. Unfrotunately cant test with VRR as ps4 pro doesnt support that. I also use this TV mostly for movies, but sometimes play games on it just because it looks so much more impressive than my pc monitor which i use for consoles too

[Toejo78]

Update is live in the UK all!

[jayh89]

It's there for every TV except mine, the 55" q85t, what!?

[Toejo78]

Im sure it will be up today

[Toejo78]

I say live but its sooooooooooooooooo slow, might be downloaded by the time the next update is released lol