GameMode not working with HDMI 2.1 (RTX 3090),Samsung 2020 QLED [1402] Update !!!!!!

[RouDeR]

Background:
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 !!!

However
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

SUMMARY:

Spoiler

Game Mode does not work AT ALL on the HDMI 2.1 port when HDMI 2.1 source is Attached.

[Chast]

"regardless of being supported or not"

"Samsung has never officially released it on their TVs"

you don't know what you're talking about. stop post. just stop

[Chast]

@RouDeR 

3. Has the HDMI 2.1 compatibility been improved?
→ Improved external device connection compatibility (meaning HDMI 2.1 compatibility).

[RouDeR]

Lets hope so !
We will find out in 2-3 weeks (normally the EU updates are late with such time-frame)

[LCDeez]

If you read the manual, it clearly states VRR at 1440p 120hz, VRR at 4K 60hz. The tv doesn’t support 4K 120 and VRR simultaneously. They lay it all out for you clear as day. 

[daparky]

Yep 100% and there's no way to disable VRR when game mode is enabled? So what if you want to play @ 120hz but VRR stops that?

[LCDeez]

We don’t legitimately know how any of this will work yet.

[daparky]

I nearly bought the Q90T as I was waiting for the firmware to fix dimming issues then i found out it's missing a key feature for next gen.

4K @ 120hz with VRR enabled is must have next gen feature.

[RouDeR]

Only way for me to test if the 4k 120hz VRR work on the HDMI 2.1 port or even 60hz in 2.1 port is for samsung to Fix the Game Mode as it doesn't turn on (screen stays BLACK as I already stated)
Game Mode is required in order VRR to be enabled on the TV, without Game Mode I don't have the G-sync menu in the Nvidia control panel, I really hope with next update the GM problem with HDMI 2.1 is going to be fixed, otherwise we will have to wait for another 2-3 months....

[FrithjofSchuon]

Hello I'm interested in that matter too, I intented to buy a q80T for next gen gaming (RTX3080) but if VRR is not compatible with 4k120, there is no point getting this TV with HDMI 2.1 at all !!

How did all the reviewers missed that in there reviews ?

Is there any way to confirm this ?!

[daparky]

No way to confirm but it is in the manual, download the e-manual and search for FreeSync. I think  a lot of people have been mislead by 4k/120hz.

It can do 4k/120, just not with VRR enabled.