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The AMD Driver Thread

Do the AMD drivers support dual 10/8-bit RGB output via HDMI 2.1?

I've just setup two Dell S2725QS monitors. I have both of them connected via the supplied (ultra-high speed certified) HDMI cables to my Sapphire Pulse 7900XT. I'm only able to set one of them to 10-bit or 8-bit RGB. The other is locked to 8-bit YCbCr420.

I've tried swapping the ports used on the monitor, swapping the connections around on the GPU but I'm always limited to one monitor being YCbCr420. The cables appear to be fine, if I plug one in at a time, they will use RGB.
 
SkeeterUK said:
Can you use dp cables instead as hdmi might not work with dual 10bit displays.
Click to expand...
I could but not sure why HDMI wouldn't work. I would have to use HDMI on my main monitor as I use the speakers on that monitor for basic listening when not using headphones. The monitors are actually 8 bit +FRC but even 8 bit RGB on both doesn't work.
 
Displayport will send sound for basic listening. Sounds like your card has a duff/cheap HDMI encoder? Could be driver nonsense too I guess.

You only need HDMI for audio if it's going into an amp for Atmos or something like that.
 
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You could try lowering the refresh rate that might lower the bandwidth maybe???? Really not sure but id probs have a quick go see if it works as a temp measure. Say if it was 120hz on both try 60hz on both. Doubt it will work as i think its the need for dp ones but u never know.

Also how bad is 10bit needed, are you into photography and need 10bit displays or could u manage if they just ran at 8bit instead, or would it be a bother. Least in the temp term till u find a more long term solution i mean.
 
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sparkymark75 said:
Do the AMD drivers support dual 10/8-bit RGB output via HDMI 2.1?

I've just setup two Dell S2725QS monitors. I have both of them connected via the supplied (ultra-high speed certified) HDMI cables to my Sapphire Pulse 7900XT. I'm only able to set one of them to 10-bit or 8-bit RGB. The other is locked to 8-bit YCbCr420.

I've tried swapping the ports used on the monitor, swapping the connections around on the GPU but I'm always limited to one monitor being YCbCr420. The cables appear to be fine, if I plug one in at a time, they will use RGB.
Click to expand...
There's a whole thread about this, it turns out that when Sapphire did the dual HDMI cards (7000 and 9000 series) they actually split a single HDMI's bandwidth between the 2 HDMI ports so they don't both get the full bandwidth. There were a few of us that were not happy when we found that out.
 
SkeeterUK said:
You could try lowering the refresh rate that might lower the bandwidth maybe???? Really not sure but id probs have a quick go see if it works as a temp measure. Say if it was 120hz on both try 60hz on both. Doubt it will work as i think its the need for dp ones but u never know.

Also how bad is 10bit needed, are you into photography and need 10bit displays or could u manage if they just ran at 8bit instead, or would it be a bother. Least in the temp term till u find a more long term solution i mean.
Click to expand...
I was using 10 bit as it was available but then I learned it’s actually 8 bit + FRC so I’ve just set it to 8 bit but even that doesn’t work.
 
GoogalyMoogaly said:
There's a whole thread about this, it turns out that when Sapphire did the dual HDMI cards (7000 and 9000 series) they actually split a single HDMI's bandwidth between the 2 HDMI ports so they don't both get the full bandwidth. There were a few of us that were not happy when we found that out.
Click to expand...
Wow, wasn’t aware of that.
 
So from reading the thread I think you are referring to. The issue is that the AMD spec is 3 x DP2.1 and 1 x HDMI 2.1.

However, some manufacturers have changed this to 2 x DP and 2 x HDMI on their cards but due to hardware limitations (in RDNA?). Running both HDMI outputs at high output settings doesn’t work fully?!
 
Think it is this thread its refering to.

9070 XT - 2x HDMI high refresh displays (144 and 120 Hz) not working

ASRock B650M Pro RS AMD Ryzen 7 7800X3D 32 GB DDR5-6000 Corsair RM850x (2018) 850W PSU (manual) I have just bought an RX 9070 XT, which will replace my RTX 3080. I used the same PSU cable that I used with the RTX 3080 (page 6 of the manual, labelled 'PCIe 8 pin (6+2) cable'). I used Safe Mode...
forums.overclockers.co.uk forums.overclockers.co.uk
 
SkeeterUK said:
Think it is this thread its refering to.

9070 XT - 2x HDMI high refresh displays (144 and 120 Hz) not working

ASRock B650M Pro RS AMD Ryzen 7 7800X3D 32 GB DDR5-6000 Corsair RM850x (2018) 850W PSU (manual) I have just bought an RX 9070 XT, which will replace my RTX 3080. I used the same PSU cable that I used with the RTX 3080 (page 6 of the manual, labelled 'PCIe 8 pin (6+2) cable'). I used Safe Mode...
forums.overclockers.co.uk forums.overclockers.co.uk
Click to expand...
Yeah that’s the one I was reading. Pretty crappy to have gimped ports on a card!
 
Sorry, yeah, I wasn't too helpful there was I, wasn't sure how to link the thread but I could've at least given you the name of the thread.
Yeah, the thread sorta goes off on a different topic but I think you get the idea and yeah, it's annoying. Probably like yourself and others part of the reason I bought the card I did was because of the 2nd HDMI port.
AMD don't seem overly worried about it but it doesn't seem like there's much that can be done with drivers as it's seems to be a hardware limitation. I've had an Nvidia card with 2 HDMI ports and it didn't seem to suffer the same issue, not sure what Nvidia did that meant it wasn't an issue on their cards.

I've switch to using an adaptor now, which isn't ideal either, but from memory I could run one card at 4K 120Hz Full-RGB/YCbCr444 and the other at 4K 120Hz YCbCr420. I do wish there was an option to run both at 4K 120Hz YCbCr422, but I don't know if that's halfway between them or just seems like that while in fact there's not enough bandwidth for that.
Would also be nice if it would consistently use the same settings, but I found at random things got all messed up regarding which port was limited and as a result what settings each one was set to.

If you can do HDMI to one monitor and DP to the other, I'd do that personally.
 
MyBrainz said:
I use O&O ShutUp10++ (its for Win 11 too) and never get this, there is a specific setting in there for this issue.
Click to expand...

Thanks for the reminder, been a while since I used it and your comment made me check and it needed an update and resetting some buttons. And I also found the windows drive update button to prevent that from working, since it was orange it was not set to prevent it. So thanks again ! :D
 
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