Can't extend 4th display, windows 8.1 R9 280x

[Dijas]

Hey all,

I've got a 280x, and 4 displays.

I have two displays attached to both of the DVI ports on my card (neither of them have adapters, just straight DVI), I have one display attached with HDMI, and lastly I have a VGA display attached with a VGA to mini-displayport.

All of these displays show up fine, except one of the DVI monitors. It doesn't matter which DVI port on the card the monitor is attached to, it still won't let me extend it.

Going into Catalyst, I see all 4 monitors. The display that wont show up is labeled with the correct model number, so I know that it's being recognized. The problem is, when I go to "Creating and arranging desktops", and try to extend windows to this 4th display, I get this error:

"To extend the desktop, a desktop or display must be disabled".

I tried doing it through windows, but when I try to extend it that way I get this error:
"The display settings could not be saved. Please try a different combination of display settings".

I'm pretty much stumped here. This card is supposed to be able to handle up to 6 displays, but I can't seem to get 4 working. Any help would be appreciated.

 

[k1114]

Any monitors above 2 need to be on an active dp.

 

[Dijas]

Any monitors above 2 need to be on an active dp.

But it's the DVI display that isn't showing up, not the DP one.

 

[k1114]

You've got 3 ports in non dp. You can only have 2. That's why a non dp is not showing. You need to use dp.

 

[Dijas]

You've got 3 ports in non dp. You can only have 2. That's why a non dp is not showing. You need to use dp.

so basically I can't actually use all of the ports at the same time? that's pretty dumb :/

I have an extra HD 7770 lying around, could I install that in my pc and then just run my 4th monitor off of it?

 

[k1114]

This dp debacle is an amd thing. Nvidia cards can use any port but they only support 4. I'm sure amd will change for the next gen because a lot of people are complaining about this. You can use your 7770. If you have integrated graphics, then you might even be able to use that. That's what I do, use my intel igpu along with my nvidia gpu for more monitors.