I'm trying to figure out why I can't get a 3rd monitor to work in Windows 7. I'm assuming that it's a software issue at this point, because the exact same setup is working on another machine.
Running Win7 Pro, there are 2 cards installed, both show up in device manager as AMD Radeon R9 200 series and have no issues, and are both enabled.
I've updated the drivers to the 7/5/16 release (16.200.1035.1001).
In the AMD Radeon settings app, they both show up under the system tab. One says AMD Radeon R9 200 Series #1 (Enabled) and the other says AMD Radeon R9 200 Series #5 (Linked).
So the problem is with the second card. Any monitor plugged into it will not show up as useable in Windows. The two monitors plugged in to the first card (this is all DVI) work fine as expected as dual screens. There is no option for #3 in the Windows display properties, and clicking identify will not put a big white '3' on the third monitor.
Everything is plugged in correctly, as far as I can tell. When updating drivers, and all the resolutions go haywire for a bit, the third monitor will light up with a perfectly good image of the desktop or whatever it is at the moment. So it *can* work, it just doesn't for some reason.
Is there some way Windows can limit you to two monitors? Any help would be appreciated.