PC Gaming on TV Game Mode woes

[Lacoaster]

Apologies if this is not posted in the correct place, I'm trying to get answers from different forums to discover if this is Hardware or Software related.
I have an issue with a Samsung QN90C TV connected to a PC that drops connection in Game Mode.
Whenever I try to start a Game in Steam with Game Mode enabled on the TV it loses connection with the PC and I am presented with a non-responsive blank screen.
If I lower the desktop resolution to 1440p I can sometimes get into a game start screen but the refresh rate is reported as 100hz instead of 120hz. Sometimes I need to toggle game mode off and back on again even in 1440p for the connection to hold but then the game screen far too big to even navigate - presumably something to do with windows desktop scaling?
Clearly something is not working as intended here.
Peculiarly, if I enable GPU scaling over Display scaling in the AMD control panel Game mode operates perfectly.
Does anyone have any clue as to what is happening here?
QN90C is new.
Certified Ultra High Speed HDMI Cable.
PC is fresh install Win 11 Pro 23H2.
Ryzen 7600X Radeon RX 6800.

Many thanks.

 

[tommybhoy]

Certified Ultra High Speed HDMI Cable.

Is it certified 4K 120Hz?

First thing I'd check is faulty cable.

My setup is two monitors connected, but only one is set to output display at any time, (mostly) Samsung is only for gaming.

Hardly ever happens but when I swap windows to output on Samsung, game mode is disabled and it defaults to 60hz SDR until I re-enable game mode it goes back to HDR/120 or oc'd to 144hz.

 

[Lacoaster]

Is it certified 4K 120Hz?

First thing I'd check is faulty cable.

My setup is two monitors connected, but only one is set to output display at any time, (mostly) Samsung is only for gaming.

Hardly ever happens but when I swap windows to output on Samsung, game mode is disabled and it defaults to 60hz SDR until I re-enable game mode it goes back to HDR/120 or oc'd to 144hz.

"Certified Ultra High Speed HDMI Cable." So, yup.
"Peculiarly, if I enable GPU scaling over Display scaling in the AMD control panel Game mode operates perfectly"
Obviously isn't the cable.

 

[HRL]

"Certified Ultra High Speed HDMI Cable." So, yup.
"Peculiarly, if I enable GPU scaling over Display scaling in the AMD control panel Game mode operates perfectly"
Obviously isn't the cable.

I think saying obviously it’s not the cable is possibly jumping the gun. Still suspect it could be the cable that’s faulty.

Do you have a different brand similar cable you can try using instead?

 

[Lacoaster]

I think saying obviously it’s not the cable is possibly jumping the gun. Still suspect it could be the cable that’s faulty.

Do you have a different brand similar cable you can try using instead?

If the cable were faulty, why would it work perfectly when scaling is done by the GPU instead of the Display?

 

[Lacoaster]

This is where the first thread was posted and what we have been through so far.

Question - QN90C 55' Game mode on Win11 PC

I picked up a QN90C 55' for £700 which seemed a bargain to me. It is hooked up to digital terrestrial, a YSP-2700 and a win 11 PC sporting an AMD RX6800. I'm not going to be gentle here, it is perhaps the second worst software of any TV I have owned in 20 years. Is there some hidden handshake or...

www.avforums.com

 

[tommybhoy]

"Certified Ultra High Speed HDMI Cable." So, yup.

Obviously isn't the cable.

You didn't answer if it's 120Hz, however, you can get a 120Hz/48gbps certified hdm 2.1 cable delivered for less than a tenner to make sure it's not the cable that perhaps doesn't like a handshake with Samsung.

 

[Grim5]

If the problem is the cable, then you'd lose image as soon as you set the driver to output 4k 120hz. The fact that the screen works and keeps working until you launch a game, suggests something wrong with the driver or GPU imo

 

[Daytrader]

You are running your tv in PC mode correct ?

 

[Blackbadger]

I have a QN90C connected to both a amd laptop and nvidia 390 system. 4k 120hz works like a dream. win11/linux doesnt matter.
The supplied samsung hdmi cable did cause all sorts of issues especially with the nvida system, as did a expensive supposedly premium cable. however a Amazon Basics 48Gbps Ultra High-Speed 8K 1.8m works like a dream, 144hz works fine also on the QN90C. Freesync and gsync both work fine.
I have never used game mode only PC mode, which I understand gives the best output, however does mean it's up to you to tune things a little more. Game mode I believe is meant for consoles. *(I reserve the right to be corrected).

Any questions, or settings, ask away.

 

[Daytrader]

Yes, never use game mode on tv with PC, change hdmi input to PC mode.