Question Display has no signal when gaming full screen at 1440p or higher ?

[Wouter_U]

Hi everyone.

I bought a new pc a few days ago but am having trouble with full screen gaming. Whenever I try a demanding game, or 3dmark for example, and run it higher than 1080p full screen at 120Hz, the TV will say that there is no signal all of the sudden. If I press Alt-Tab or press the windows key etc, the screen will come back. But the signal is lost again when I try to go back to the game. Also with less demanding titles it seems it does work even with 4k 120Hz.

I can run everything at 1080p full screen, but I bought a 4k 120hz display for a reason.
In windowed mode it works just fine, but a lot of applications default to full screen, So I do want this fixed.
One thing that I do still need to upgrade is my HDMI cable. It's an older one and not hdmi 2.1. But this was never a problem before with my old pc, so I'm not sure if this could really be the issue. Also I've noticed that the game does keep running while the screen loses signal. i can still click on things and when alt-tabbed I can hear the music and sounds of the game and when hovering on it on the taskbar I can see the screen preview.

Things I've tried:
Updating Drivers/reïnstalling drivers
Clean Windows install
Checked if cable is connected to correct HDMI ports
Tried with G-sync on and off
disabling variable refresh rate on TV
Tried 4k on lower Hz

My system specs:
CPU: AMD 7800X3D
GPU: MSI gaming x slim RTX 4080 Super
Motherboard: Asrock A620I
RAM: 32Gb Corsair Vengeance at 6000hz
PSU: Cooler Master V SFX Gold ATX 3.0 850W

TV:
TCL 55C745

i hope someone can help me because if a game defaults to full screen I am just unable to play it.

 

[Imperat0r]

Hello.
In order to determine if it's monitor's fault, you have to use the monitor on another device which supports both 4k and 120Hz.
After you determined that the monitor is ok, you will reinstall video drivers and you will try again on that monitor.
Keep in mind that the video cable is a MUST.
So having a lower specs cable is a true error.
I would start first with that but this time i would use a Display Port cable

 

[Wouter_U]

I don't have access to another 4k display unfortunately so I can't really test it.
As stated in my post I already reïnstalled drivers and even Windows.
An HDMI 2.1 cable is on the way and I will test that out. I just don't understand how it can possibly be that this suddenly starts happening the day I get a new pc. On the same day with my old pc it did work on 1440p at 120Hz.
I can't use a displayport cable unfortunately because the display (a tv) only has HDMI.

 

[Imperat0r]

OK, then if you don't have display port you will use what you have.
And yes we will wait until you receive the new cable to make some tests.
Good luck mate!

 

[Wouter_U]

It seems that the new cable has solved it. Still I do not understand why it suddenly stopped working when I got my new pc, as it had worked before with my old one. Also why it only decided to not work with full screen games and not with full screen 4k video for example. But whatever the reason, I can finally enjoy my setup.
Thanks for the support

 

[Imperat0r]

We are glad that you solve it.
Cheers mate!