I have a 3 screen eyefinity setup (4800x900) on a XFX Dual Disapation Radeon 280X card. I use the 2 DVI ports and one active mini display port. I have the 14.6 beta drives currently, and had the same problem with 14.4
I have my computer set to power down the monitors after 5 minutes of inactivity. It never goes to sleep.
After I bring the monitors back working, the monitor attached to the mini displayport only uses the middle of the monitor, like it was a 1024x768 monitor rather than the 1600x900 it should be. It pretty much take a reboot to get things back how they should be.
Any ideas how to get all my screens to come back full screen every time?