Question AMD 7900 XTX - - - black screen on HDMI/DisplayPort ?

[ukexplicit1984]

Hi all, basically I got a new pc the other day and have been having this issue. PC is connected to a 4k TV. If I connect via displayport to hdmi it works fine but is limited to 1080p. If I connect with hdmi it shows the bios screen then black screens. If I connect both and duplicate displays on separate TV channels they both work and I can change the display to 4k. But if I remove the displayport, the hdmi no longer functions and black screens.

I have googled to no avail and it's doing my head in! I know the displayport to HDMI allows 4k as it did it on my previous build and allows me to change it to 4k once the HDMI is also plugged in. I can't just leave both plugged in as I need the HDMI slots on the TV for other things.

All drivers are up to date and the cables and ports are clearly working.

Specs:
Motherboard: MSI Mag 670E Tomahawk
GPU: Radeon 7900 XTX 24GB
CPU: AMD 7800X3D
RAM: 32GB 6000mhz
PSU: Corsair 1000w

If anyone has any suggestions I would be hugely grateful!

 

[JohnBonhamsGhost]

what length are any HDMI cables being used and what iteration of HDMI are they?

provide link to cables and/or any adapters being used.

 

[ukexplicit1984]

what length are any HDMI cables being used and what iteration of HDMI are they?

provide link to cables and/or any adapters being used.

Display port to hdmi is this one:

https://www.amazon.co.uk/dp/B015OW3P1O?ref=ppx_pop_mob_ap_share

Hdmi cable that only works when display port is also connected

2.1 HDMI Cable 8K, IBRA 2m Ultra... https://www.amazon.co.uk/dp/B07WN8C7XV?ref=ppx_pop_mob_ap_share

I have tried other hdmi cables that I have kicking about. Nearly all of them work as long as the display port is connected and I am extending or duplicating the displays.