Proprietary drivers in Ubuntu are drivers for your hardware devices that are not freely-available or open source, and must be obtained from the hardware manufacturer. The free and open source video driver, Nouveau, is the driver Ubuntu will use as the default for Nvidia graphics cards. Nouveau does not have support for 3D and may not work at all with latest video cards from Nvidia. Proprietary drivers, closed source, are the alternative for Nouveau, and most of the time provide superb 3D acceleration and overall video card support/performance.
AMD/ATI graphics or video cards also maintain and develop a proprietary driver that is designed for use in the Ubuntu Linux system. This driver is named "fglrx". An important note is that although these drivers are available they are not necessary -- as they are with the Nvidia drivers -- to enable 3D accelaration.
Some hardware devices may require proprietary drivers in order to function properly when attached to your computer. Installing the appropriate proprietary driver for your device, specifically a video card, can add increased functionality in Ubuntu and allow the use of more advanced visual effects.
One key thing to keep in mind when installing proprietary drivers on your Ubuntu computer system is that they are often maintained and updated by the manufacturer. Therefore Ubuntu developers are not able to modify the driver in order to correct problems with it.
Step 1. Add additional drivers. Click the power symbol located in the top right corner of the screen. This will bring up a drop down menu. Select "System Settings."
Step 2. Once in the system settings control panel, select additional drivers. Ubuntu will now search for all installed proprietary drivers, and will also search the web for updates to them. After you install the restricted/proprietary drivers it is a good idea to reboot your machine.
If you have installed Ubuntu 11.10 (Oneiric Ocelot) or version 11.04 you will need to install a proprietary driver to run Unity 3D rendering if you are using an additional graphics card not supported by the OpenGL (Open Graphics Library) graphics. Without a 3D graphics driver Unity will run in 2D mode and you will miss out on all of the awesomeness of the 3D desktop.
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update
sudo apt-get install nvidia-current
If you notice that a proprietary driver you have installed is causing problems or you would like to remove it for some other reason you may want to disable it.
For this you all you need to do is follow the same instructions above but instead of activating the driver you will want to press remove.
**Note: You may need to restart your computer in order for the changes to take effect.
Installing a new video card? Well choose carefully. Some video card manufacturers/graphics card manufacturers may require the use of restricted, non-open source (non-free) drivers for the graphics hardware to function properly. This can be problematic since the code for the driver is not freely accessible by Ubuntu developers and they are unable to modify the code. Only the manufacturer will be able to do this so it is up to them to provide appropriate updates as needed.
Graphics card manufacturer Intel, does not require restricted drivers for their products to function on an Ubuntu system. The drivers for Intel cards are free and open-source and come packaged with Ubuntu desktop.
For Nvidia cards, Ubuntu includes a generic Nvidia graphics card driver, however it has limited functionality and lacks 3D acceleration capabilities. Up to date Nvidia graphics card drivers are available from the Nvidia Support Website.
ATI Cards also have a generic driver included with Ubuntu that does provide for 3D hardware acceleration. However with newer cards you may need or want to install the restricted driver. "fglrx" is the name of the proprietary AMD/ATI that can be used for graphics cards with an AMD/ATI graphics processing unit (GPU).
Check this out for more help on installing restricted drivers for ATI devices. Restricted ATI Driver Installation