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.

 

[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.

 

[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

 

[Lacoaster]

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.

Uh, well I did but I also assumed that you were familiar with HDMI certification having a naming protocol, High speed, Premium High Speed, & Ultra High speed. Apologies for the confusion.

By definition certified Ultra High speed cable has to be capable of a minimum of 8k@60Hz & 4k@120Hz & 48Gbps bandwidth.
2.1 & 2.1b are spec revisions that relate to features within the certified capabilities of Ultra High Speed cable as I am sure you are aware like VRR, ALLM etc.

Ultra High Speed HDMI Cable - Bandwidth Up To 48Gbps

Looking for a high speed HDMI cable? ✓ Click here to learn about high speed vs ultra high speed HDMI cable specifications & certification program compliance! HDMI 2.1b

www.hdmi.org

As you can see from the thread I started in AVForums I went down the exact same though process as you - just buy another (this is the second) certified HDMI cable from another manufacturer to 'double check'.
However, once I had established that the current cable was perfectly capable of stable game mode connection in 4k@120Hz due to switching the scaling from the TV/Windows subsystem to the GPU/AMD Driver then the need to establish the capability of the cable disappeared. Unless ofc, changing scaling from Display to GPU somehow switches out the handshake? It is still physically attached to the Samsung isn't it?

 

[Lacoaster]

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

I've worked with analogue and digital AV on & off for 20 years and I would have to agree. It is possible to have a bad analogue connection. Digital either works or it doesn't.


When you say 'something wrong' do you mean faulty, corrupt, or perhaps a bug or incompatibility?
My sense at the moment is that the TV & Windows display sub system do not play well either with each other or with the GPU hardware or software.

 

[Lacoaster]

You are running your tv in PC mode correct ?

If you read my 'rant of frustration' at the beginning of the thread I started in AVForums, you'll see that connecting a Samsung TV to a PC leaves you with little choice but to have it running in PC Mode. So the answer is yes, it is in PC Mode.

 

[Lacoaster]

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.

Thanks very much for the offer. You may live to regret it

I think perhaps you have either the 43" or 50" model of QN90C. They are the only models that are 144Hz capable. They also have different panels. Not sure what other differences there might be. My QN90C is the 55" Model.
How do you enable Freesync without turning on Game Mode on the display?

 

[Lacoaster]

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

According to who?
I have been gaming on PC & Console on TV's for the better part of 20 years and I have never read a single tech based article that states TV game Mode should not be used on PC.

 

[Lacoaster]

Well first, as soon as you turn on game mode, it turns off a lot of the picture options that make the picture look good, i like to have full control over all the picture settings, thats the main reason i think.

Again, as revealed by my opening rant about the Samsung set up that decides what is best for you, I couldn't agree more about picture settings but one can still set it to give you the picture that you desire, it just takes some getting used to and some initial set-up.
There is certainly no technical reason for not using the features that TV game Mode offers on a connected PC that I know of. One of the prime reasons for me is Variable Refresh Rate. I cannot stand stuttering or tearing and vrr is a god-send.


This fella does a good job of going through all of the Picture settings for this particular TV Model.