First of all it's kind of sad when ATI do not have a proper driver for linux. But thanks to the dev team who did a great job by making our ATI Graphic card useful nowadays. But the ATI driver do not load automatically after a fresh install of ubuntu(any version). So you cannot load any desktop effect(compiz). To enable desktop effect you have to install ATI driver from the restricted area. This how you can install ATI driver:
- Open System>Administrator>Restricted Driver Manager
- Tick for ATI restricted driver.
- This will install the driver automatically.
- After installation, you'll be ask for reboot, you need to reboot to run the new driver.
- Open Terminal ( Applications>Accessories>Terminal)
- type sudo apt-get install xserver-xgl
- This will install the XGL server.
- On Gutsy Gibbon, the XGL will load automatically on start. But on feisty or any previous version of Ubuntu, you will need to do a few things to load XGL on startup.
- Follow instructions here to enable XGL on start up. XGL help.