I got Sapphire R9 290x, three screens (Dell U2412M), two of them connected via DVI, one via Displayport.
Now everything was ok, when on Windows 7, running AMD-Catalyst-15.6-Beta-Software-Suite-Win7-64Bit-June22 drivers.
Using newer drivers on Win 7 (15.7 or 15.7.1), or migrating to Windows 10 (any drivers) causes the problems. The problems appears after a while in 2D mode (desktop), or sometimes when exiting 3D application to 2D and also when the computer wakes up.
The problems includes horizontal flickering and image tearing, very annoying, across all the screens. It seems that when moving the mouse or a window, the flickering is much more frequent. Whenever the display adapter is restarted, the problem disappears for a while. Fullscreen application does not seem the be affected by the flickering, but I have discovered that some of them (even benchmarks) might cause the computer to hard lock (hard reset required).
Temperatures are nominal, changing the core or memory frequencies does not affect it at all.