I have just added a second 980TI to a system. I have 6 monitors connected to the 2 cards. Primary GPU has 2x Dell U2412Ms connected. All 3 are connected via Display Port on the cards to DVI-I on the monitors. On the second card I have 2 ViewSonics VX2349Ws connected the same way and an NEC LCD2070WNX that is connected via DVI-I.
Now for the fun: no matter how I attempt to configure the system, I can not get it to span all 6 monitors. Base Mosiac works with 3 (the original configuration that I had setup) but Base Mosiac only supports a MAX of 3. I am looking to have all 6 on the same x server with the ability to full screen an application on any single monitor.
I have constructed multiple xorgs including 1 that has 6 defined monitors and devices with Xinerama enabled but X will either come up incorrectlyl or Cinnamon will not start.
Resolutions on the monitors
Dells- 1920x1200 (bottom in line)
Viewsonics & NEC 1680x1050 (top in line).
Looking for any hint to start with.