I use three 2560x1600 monitors, each with their own Radeon HD7850. When playing Civ5 or Eve Online the screen will freeze for a couple of seconds (and more) intermittently when panning the view in Civ5 or rotating the camera in Eve Online. This problem doesn't occur if I simply disconnect two of the monitors (leaving their graphics cards in). I've tried swapping cards out with a new R9 390 with no change in behavior.
This behavior is new and began after I updated the graphics drivers - the previous drivers would not allow Fallout4 to run. Fallout4 has no problems running now with all monitors connected but now I can't play EVE Online without disconnecting monitors. The MB is a Gigabyte GA Z97X - its site is reporting no updates to the bios affecting graphics behavior. Crossfire is not enabled and the bridges are not installed.