I have purchased an active display port to hdmi adapter in order to get to a third display functioning on my computer. It will finally detect the third monitor, which it would not do before. It remains disabled though, and I can't figure out how to get it to work.
What error messages are you getting from the third Monitor in Windows or Radeon settings?
Could your Active DP-HDMI Adapter be the problem? Or the HDMI cable connected from the adapter to the monitor? What resolution do you have your monitor set at in Windows for the third monitor?
What is the Make & Model of the Active DP-HDMI that you are using?
EDIT: Needed to delete some information since the OP accidently gave the wrong GPU card model.
My bad. R9 200 series. All monitors are set to 1920 x 1080. Each individual monitor works on the system. Any combination of two work, and the second a chord is unplugged, the third will turn on. All drivers are up to date. There is no error message. When you choose extend screen in display settings it just autoresets itself to "disconnect this device." I've tried every combination of VGA, HDMI, Display Port, DVI-I, DVI-D, cables, and DVI-D adapter to VGA, display port to hdmi, dvi-i to vga adapters. No matter what I can't get the third to function simultaneously. UltraAV® DisplayPort 1.1 to HDMI 1.4 Active Adapter is the active adapter.
Okay here is the latest AMD Driver for the R9 2xx series GPU Card: AMD Radeon™ R9 270 Drivers & Support | AMD .
It is possible you Active DP 1.1 adapter is not compatible with the monitor. The R9 2xx Series GPU card has DP version 1.2 on it. You may want to see if an Active DP 1.2 adapter will work.
From AMD Support about Multi Monitors on the R7 and R9: How do I connect three or more displays to an AMD Radeon™ R series graphics card?
The AMD Radeon™ R series graphics card can support up to 6 displays, with the exception for the R7 250/240 which can support a maximum of two displays.
The table below illustrates the combination of outputs that can be used with the number of connected displays. Please note when connecting 4 displays, one of the displays must be connected using DisplayPort™ output.
R9 290X/290 | R9 280X | R9 270X/270 | R7 260X | R7 250/240 | |
Maximum displays supported | 3 with DVI/HDMI 4 using DisplayPort 6 with an MST hub | 3 with DVI/HDMI1 4 using DisplayPort1 6 with an MST hub | 3 with DVI/HDMI1 4 using DisplayPort1 6 with an MST hub | 3 with DVI/HDMI 4 using DisplayPort 6 with an MST hub | 2 |
So when I look on my computer it says it's r9 200 series. The card and tower both say it's r9 370 though. Not sure why it's different. The display port adapter is the "certified" product for this specific card. Even with those chords, and connections I still can't get that third monitor to function together with the other two. I'm seriously lost, and frustrated about this haha. Tried taking it to two local computer places, and they can't figure it out. Their only suggestions have been to try an MST adapter which is next on my list of things to try. For the price of one of the MST's I could honestly just drop money on a new card, and it would probably work just fine.
Update... I got in to BiOS and enabled my motherboards VGA port. All three monitors currently working. Still no solution for running more than 2 on my GPU though.