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Did I just screw up with the 7900XTX - multi monitor supported?!

J

jeconti

Joined
Nov 8, 2018
Messages
29 (0.01/day)
I was super excited to upgrade from my 2080 Super 8GB to the 7900 XTX 24GB. My old 2080 had 3 DP outs, and I had 3 monitors connected to them. The 7900 XTX has 2 DP, 1 HDMI, 1 USB C. I have 2 DP and 1 HDMI plugged in, and the HDMI is not detected and nothing I am doing is working. Does anyone know of any tricks, if this might just not be supported, is it DP OR hdmi, not both?!
 
jeconti said:
I was super excited to upgrade from my 2080 Super 8GB to the 7900 XTX 24GB. My old 2080 had 3 DP outs, and I had 3 monitors connected to them. The 7900 XTX has 2 DP, 1 HDMI, 1 USB C. I have 2 DP and 1 HDMI plugged in, and the HDMI is not detected and nothing I am doing is working. Does anyone know of any tricks, if this might just not be supported, is it DP OR hdmi, not both?!
Click to expand...

It should be plug & play, or just works.
If it doesn't, it is of your right to return the card.

It has so many negatives, that I honestly wonder who in their right mind would be happy to own such a thingie.
 
jeconti said:
I was super excited to upgrade from my 2080 Super 8GB to the 7900 XTX 24GB. My old 2080 had 3 DP outs, and I had 3 monitors connected to them. The 7900 XTX has 2 DP, 1 HDMI, 1 USB C. I have 2 DP and 1 HDMI plugged in, and the HDMI is not detected and nothing I am doing is working. Does anyone know of any tricks, if this might just not be supported, is it DP OR hdmi, not both?!
Click to expand...
No reason it should not support it. If it wont come up check the drivers and see if there is something disabled. Also try just using the HDMI only and see if anything comes up.
 
jeconti said:
I was super excited to upgrade from my 2080 Super 8GB to the 7900 XTX 24GB. My old 2080 had 3 DP outs, and I had 3 monitors connected to them. The 7900 XTX has 2 DP, 1 HDMI, 1 USB C. I have 2 DP and 1 HDMI plugged in, and the HDMI is not detected and nothing I am doing is working. Does anyone know of any tricks, if this might just not be supported, is it DP OR hdmi, not both?!
Click to expand...
On the 6900Xt reference I use 2x Displayport and a USB C to displayport - some bugs in windows 10 - fixed by plugging in and out the USB C. None so far in windows 11
 
jeconti said:
The 7900 XTX has 2 DP, 1 HDMI, 1 USB C. I have 2 DP and 1 HDMI plugged in, and the HDMI is not detected and nothing I am doing is working.
Click to expand...
I'm guessing you already verified that the monitor source is set to HDMI?
 
Check that hdmi cable maybe is losing contact somewhere or maybe is older ver. and simply can't do 4k+ high refresh rate if you trying that....try lower res and refresh rate just to check if HDMI is working on yours GPU....GL
 
1. Monitor source set to HDMI
2. Highest quality HDMI cable
3. Windows -> Multiple displays
4. Radeon Software

It's also possible for some reason the card sends signals via the DP ports but doesn't to the HDMI port at the same time.

You can also try to use the monitor's DP port with a DP cable and HDMI-DP adapter to the card.

1671136566035.png
 
I've tried everything above and no dice, known working hdmi cable as I used it on another machine. And the monitor is an older one I use vertical on the side for reddit/doomscrolling. 1080 24inch. I'm going to order the cheaper of those 2 adapters mentioned here and see if I can find success.

Detect displays, firmly seated cables, everything enabled. So weird.

Came back to share some interesting new results as I played with combinations of all things mentioned here.

Just the HDMI plugged in, that 1 monitor works.
Add 1 DP monitor, now I have 2 monitors (1 DP, 1 HDMI)
Plug in third monitor on 2nd DP - it does not load.

So now I am in a new and interesting state of 1 DP monitor and 1 HDMI monitor. But whatever the third monitor in initialization is, does not load. I know from previous experience outputs are numbered from the far left to the far right in ascending order, so it makes sense when booted up with all 3 populated it would be the HDMI as the highest numbered input to not work.

Something is cutting off a third monitor from working and I cannot find what. I wouldn't even know where to look. Windows display settings to detect displays does not work, nothing in radeon software has a setting to enable or disable outputs.

Any other ideas besides using adapters for the USB output?
 
What are your software versions? Windows 10?
What driver version?
What monitors and refresh rates?

We need all the details you can provide.
Maybe try to install a fresh Windows from another version. If you have 10, then install 11. If you have 11, then install now 10.
Try with another driver version.
 
Windows 11 22h2 build 22621.963, Latest Radeon drivers 12.12.1. The 3 monitors are 5120x1440@120hz, 2560x1440@120hz, 3840x2160@60hz.

Swapped back to old 2080 and everything worked at correct refresh rates, resolutions, etc. swapped back to 7900xtx, same symptoms.
 
Install a fresh Windows without any nvidia drivers.
Also, try to make the three monitors running at the same refresh rate of 60 Hz and see if this would fix the problem.

Are you duplicating or extending the displays?

Duplicating Displays​

In Duplicate mode, the same image appears on all displays. The displays will run using the highest common resolution and refresh rate.
For example:
  • Display #1 has a native resolution of 1920x1080 at 75Hz refresh rate
  • Display #2 has a native resolution of 1280x1024 at 60Hz refresh rate
  • Both displays will run at 1280x1024 at 60Hz in Duplicate mode

Enabling Extended Desktop​

In Extended mode, the Desktop is extended across multiple displays to maximize the work space. The displays can have different screen resolutions, refresh rates, and orientations (Portrait and Landscape) when configured in Extended Desktop mode.
The next section of this document covers:
  • How to Enable Extended Desktop Mode
  • Arranging the Displays in Extended Mode
How to Configure Displays in Duplicated and Extended Modes | AMD
 
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I did a DDU clean uninstall and power down each time and fresh driver installs with clean install option always checked. Extended, as they have always been.

Definitely not doing a clean windows install to get multiple monitors to work, this seems ridiculous and I literally do not have the time.
 
jeconti said:
I did a DDU clean uninstall and power down each time and fresh driver installs with clean install option always checked. Extended, as they have always been.

Definitely not doing a clean windows install to get multiple monitors to work, this seems ridiculous and I literally do not have the time.
Click to expand...
Good luck then find the time to fix it then
 
This is a bit odd indeed. My suggestion while unfortunately needing another cable is try TypeC to DP its technically a “3rd DP” why “mixing“ cables is an issue with this especially as they are the latest spec which can only bring me to one possible is the HDMI is 2.1 but like most spec should have no problem doing fallback either.
 
jeconti said:
Are you trying to say that it is reasonable to expect people to do a fresh OS upgrade just for upgrading a GPU? that's insane.
Click to expand...
No but it's reasonable for you to try some simple things to get it working, it's rather simple to run windows from any spare SSD or hard drive for testing, or bootable linux from a USB drive and see how things work

There's always alternatives, but a bad attitude and refusal to try anything won't solve problems


Trying another OS is a valid step because people run all sorts of dumb tweaks and fixes to their OS that it doesnt need and it breaks things, I dont even recommend people use driver cleaners as they're a last resort not the first one - they CAUSE problems more than they fix them, yet stubborn people never learn and run in a damn loop.
I've got two different AMD drivers and an Nvidia driver in my VR PC as i swap GPUs in and out of it, and it's got zero issues - yet people tell you to run driver cleaner for swapping a monitor


The 7900XTX has three displayports (One with a USB-C connector) and one HDMI 2.1
At least 3 of the four should work together at any given time, but you'd need to try one monitor at a time with one cable and find out what's going on.
No one else is going to have your exact monitor setup, so spend that time and try that HDMI Cable and get it working on a single display, and then add DP monitors one at time until an issue occurs and proceed from there
 
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jeconti said:
Are you trying to say that it is reasonable to expect people to do a fresh OS upgrade just for upgrading a GPU? that's insane.
Click to expand...
I think it has to do with removing conflicting video drivers/software when switching from nvidia to amd or vice versa. It has only been out a few days, amd might take a little while to get the drivers right..
 
Does it work in duplicate mode? Try changing to duplicate mode and if it works, change back to extended mode.
 
Savage89 said:
I think it has to do with removing conflicting video drivers/software when switching from nvidia to amd or vice versa. It has only been out a few days, amd might take a little while to get the drivers right..
Click to expand...
That's never been neccessary, the worst you get is the amd software popping up at boot with an error that it cant find an AMD GPU

AMD drivers dont install for nvidia cards, they dont do this
 
jeconti said:
Are you trying to say that it is reasonable to expect people to do a fresh OS upgrade just for upgrading a GPU? that's insane.
Click to expand...

Sadly, it should be known to anyone that's savvy enough with tech and has used Windows (especially Win 10 and 11) long enough that the past two iterations of Windows everyone has seen some sort of f-up from MS and the crappy updates they've pushed out.

I've experienced all sorts of issues with Windows 10 updates that ranged from having to re-install drivers to get things working again or having to do complete re-install of the OS because something broke and even doing a system restore doesn't fix it.
 
This stuff shouldn't be happening on such an expensive card, hope you sort it.
 
neatfeatguy said:
Sadly, it should be known to anyone that's savvy enough with tech and has used Windows (especially Win 10 and 11) long enough that the past two iterations of Windows everyone has seen some sort of f-up from MS and the crappy updates they've pushed out.

I've experienced all sorts of issues with Windows 10 updates that ranged from having to re-install drivers to get things working again or having to do complete re-install of the OS because something broke and even doing a system restore doesn't fix it.
Click to expand...
To be fair, that sort of thing has been happening since windows 3.1
Just that these days we're easily able to find someone else with the same issues, instead of being confused about why things don't work right forever

Every OS has bugs issues and problems, it's just a fun clickbait trend to explode modern issues out of proportion
 
Be sure to double check device manager for monitors that show up once "Show hidden devices" is enabled. Remove anything that shouldn't be listed there, like old displays.
 
Mussels said:
The 7900XTX has three displayports (One with a USB-C connector) and one HDMI 2.1
At least 3 of the four should work together at any given time, but you'd need to try one monitor at a time with one cable and find out what's going on.
No one else is going to have your exact monitor setup, so spend that time and try that HDMI Cable and get it working on a single display, and then add DP monitors one at time until an issue occurs and proceed from there
Click to expand...
I already tried this step and posted results above. Spent plenty of time testing with this last night, the results were the same every time;

HDMI only, works fine. correct resolution and refresh rate.
Plug in 2nd monitor via DP - both work fine, correct resolution and refresh rate. Does not matter which monitor I use 2nd.
Plug in 3rd monitor via DP - HDMI monitor disabled. Does not show in device manager, not via show hidden, not via windows detect displays--nothing. It's like the HDMI port just fucks off and goes home.

The USB-C to DP cable arrived this AM and I swapped to that, it all works.

The HDMI cable is a known good I took from my home theater system, displaying a 75" 4k smart tv with ARC, running the latest HDMI standard.

This card just does not handle HDMI as a third monitor it seems.
 
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