How to get dual-monitor setup without mirroring Fedora 17

Question

I have a Radeon HD6570 graphics card with 2 1280x1024 monitors connected and the AMD drivers installed. However, when I try to set both monitors on without mirroring, I get an error message saying that the requested resolution is greater than the maximum available virtual resolution.
Before I installed the AMD drivers this dual-monitor setup was working just fine, how can I get these monitors to work again?

EDIT: I bought an NVidia card, and it worked perfectly out of the box.
However, while no longer relevant to my situation, I would still like to see an answer to this, as I know I'm not the only one who has this issue.

(unless the answer actually is "buy an NVidia card.")

Answer 1

In my case,

• in 'Displays' settings uncheck 'Mirror displays'
• then just open AMD Catalyst Control Center as root
• in Display Manager chose option for Multi-display desktop with display(s) (2)
• Reboot
• Open AMD Catalyst Control Center and set it like before
• Apply.

If you use cairo-dock ... I had to recheck 'Use xinerama'.

I have Fedora 17, Gnome 3.4.2, kernel 3.3.4-5dc17.x86_64, ATI HD4890 with AMD Catalyst™ 13.1 Proprietary Linux x86 Display Driver released in 1/21/2013.