ATI Graphics Drivers: FGLRX vs Open Source
This article shows the differences between FGLRX and open source ATI drivers. To install FGLRX, see this article. For the light reader, there is a summary of the article at the bottom of the page.
What is the open source driver?
If you have a linux desktop, have not installed any drivers for your graphics card, and can see pretty YouTube videos and desktop animations, you are probably using an open source driver. There are a few open source drivers, however, the most common driver by far is called 'radeon.'
It is entirely open source and the default ATI driver for Ubuntu.
What is FGLRX?
Got an ATI graphics card and haven't installed any linux drivers for it? Odds are you aren't using FGLRX. Fglrx is the common name for the proprietary driver AMD releases for their ATI Radeon graphics cards. It is downloadable from AMD's website for most of their ATI Radeon desktop and notebook cards.
Benefits of radeon
If you use an Ubuntu-based distro, you don't need to go through the process of downloading, installing, crossing your fingers and rebooting your machine. The open source drivers just work out of the box.
It is 'free'
Radeon is open source. It is created without strict copyright regulations, and in most cases can be distributed freely. Some people stick to this philosophy, and therefore stick to using open source software (OSS).
Benefits of FGLRX
For playing Youtube videos, web surfing, and photo editing, the performance difference is negligible (from what I've experienced). But when it comes to 3D intensive tasks - such as games - there are speed improvements.
Battery-wise, there are contradicting results. Some find FGLRX works better, and some find it a battery drainer.
As you can see, there's no clear cut winner. FGLRX is better for those who play games and need the performance boost, while the open source radeon drivers gets the job done easily for a bunch of folks.
Installing drivers can be a risky task. Something might not configure properly, and you reboot your computer to see a black screen. Therefore, it's best to consider the (albeit, small and potential) risk of rendering your computer unusable until you have time to troubleshoot it.