ATI graphics card, with gnome shell, screen flickers

Solution 1:

The last AMD drivers (11.10) still has problems like screen flicker but you can reduce the screen flicker active the Desktop Free of Fragmentation in the Catalysm but may cause other errors and the system feels slower, to run Gnome-shell without problems install the open source drivers. check this ATI - Ubuntu Oneiric Installation Guide, install/unistall/remove, etc... open source drivers or privative drivers

Solution 2:

This didn't completely fix the issue for me, but it made a significant improvement. I have a Radeon HD 5770 in my desktop connected to a 24" Acer Monitor via DVI, so YMMV.

1. Open up the Catalyst Control Center.
2. Expand "Display Manager" in the pages tree on the left.
3. Select your monitor (in my case "Digital Monitor (1)"
4. Click the "Adjustments" tab on the right part of the window
5. Change "Image Options" to "Use graphics processor for scaling"

Varying the "Graphics processor scaling" didn't seem to make a difference, but the transition to the Activities view is considerably cleaner, if not perfect.

Hope that helps a bit until we can get a permanent, real fix!

Solution 3:

In my case I am using an Asus laptop with Radeon HD 6470M I enabled the Tear Free Desktop under Display options within the catalyst control center and it fixed the problem.