I'm running Ubuntu 10.10 on my Dell XPS 16 laptop with Radeon HD5730 video card. I'm using the stock kernel (2.6.35-27-generic #48-Ubuntu) and fglrx driver that Ubuntu installs with the "Additional Drivers" tool. The biggest issue I have with it is the inability to enable/disable an external display without a logout (X restart?). I have tried doing this with both Catalyst Control Center and the Monitors tool (gnome-display-properties).

1. When I enable the external display using Catalyst, I see the red "2" flash in the bottom right corner of my laptop display but the external stays disabled. Catalyst says I need to restart. When I restart I see grub and the startup screen mirrored in both but after logging in the external stays disabled. When I try to enable it again in Catalyst, I see the message:
The current settings cannot be applied. Possible issues may include:
-Display(s) cannot be enabled.
-Settings(s) cannot be applied due to insufficient video memory
After enabling it using Monitors, it works.

2. If I don't use Catalyst at all and just use Monitors, my experience is better. I can enable the display, log out/in and it will work.

Is this something I just have to live with it? Could trying a newer driver work? I'd be fine with using the open source driver if it supported compositing and wasn't so slow at playing video. Any other suggestions? I was really hoping that getting an ATI card over Nvidia would mean better Linux support but alas.