First, I installed Ubuntu 13.04.
I have an ATI Radeon HD 7850.
The open source drivers allowed multiple displays, but were horrendously laggy (even opening a browser window took several seconds). When I installed the Catalyst proprietary drivers, performance was perfect. The only problem is that trying to enable dual-monitors in the Catalyst center was grayed out and in the Ubuntu settings resulted in the resolution error.
Is there any way around this?
Here is the quote from the error box when trying to change display settings.
The selected configuration for displays could not be applied
required virtual size does not fit available size: requested=(3840, 1080), minimum=(320, 200), maximum=(1920, 1920)
Here is the grayed out option in Catalyst...