Switchable graphics in Ubuntu
Solution 1:
AMD switchable graphics is now available in Ubuntu as well but it doesn't support automatic switching. You have to manually select the GPU that you wish to use.
To enable it eneter this command in the terminal,
sudo apt-get install fglrx
After the drivers have installed, restart your computer. Once it has restarted,
sudo aticonfig --initial
and restart again.
Once it has restarted again, Run AMD Catalyst Control Centre (Admin mode) from the dash and head to switchable graphics section. Switch to your desired card there.