TV is 75 inch Q800T (EU version), but I assume this will affect all of the 2020 Samsung TVs
Software is version 1402.6 (updated Octomber 8th)
HDMI Cable 2.1 certified full 48gbps
The same HDMI cable works just fine with HDMI 2.0 GPUs like my old GTX 1080Ti (Game Mode works flawlessly there)
Current GPU: RTX 3090 with latest Nvidia drivers
What is working as intended when using the HDMI 2.1 port and RTX 3090 as a source::
* Outside of game mode I don't have any problems, I can run at 4k@120hz RGB 10 bit or 8k@60hz 4:2:0 10 bit without any problems.
What does NOT work when using the HDMI 2.1 port and RTX 3090 as a source:
* If you turn on Game Mode, the TV picture goes BLACK and it looses signal
This happens disregarding on what resolution and refreshrate you are playing, I`ve tried the following:
- 1440p@60hz Input Signal Plus ON
- 1440p@60hz Input Signal Plus OFF
- 1440p@120hz Input Signal Plus ON
- 4k@60hz Input Signal Plus ON
- 4k@60hz Input Signal Plus OFF
- 4k@120hz Input Signal Plus ON
- 8k@60hz Input Signal Plus ON
NONE of them was able to switch to Game Mode !!!
If the RTX 3090 is connected to one of the HDMI 2.0 ports of the TV, Game Mode is perfectly functional, but then you are restricted to 4k60hz and 8k@30hz
Yeah but you can set whatever customer resolution is missing is my point. Maybe tey Put it in a lower resolution first and then turn on game mode and then switch back? That worked for me most of the time if game mode wouldn't activate at all. Also, you obviously can't use 8k for gaming anyway so you need to get 4k working properly in game mode.
I can't set custom resolutions. It's greyed out and not selectable.
I can't put it in lower resolutions as I get a no signal error.
I use 8k for gaming with a lot of games. If a game hits 4k 120hz then it can do 8k 60hz fine with a few tweaks.
Ok, heres my fix. use Custom Resolution Utility to 'reset all', then 'restart'. Set the resolution to 4k 60hz. Once there put on game mode (which enables Input Signal Plus). Once monitor is at 4k 60hz with input signal plus on, 8k Native res should appear. I clicked enable 8k resolution with 4:2:0 10bit (nvidea control panel). It didnt work 5 times, keep trying, and randomly it works. The key seems to be YCbCr420 mode (4:2:0). GLA - props to Wickfut!
Not sure if this issue has now been fixed for you, but it doesn’t effect all 2020 tvs I have the q95t and game mode works without issue. Sorry this doesn’t help you but just saying it’s not all tvs
Has anyone tried a Samsung monitor running 8k resolution on colour settings other than 4:2:0? The chroma subsampling isn't ideal for using as a work monitor with text. Maybe different graphics card or different 8k monitor entirely? Appreciate any info on this. ATB