Phoronix looks back at the developments in open-source AMD/ATI Radeon drivers over the last two years, you can read it over here.
"The open-source ATI/AMD Radeon Linux driver stack has made a
lot of improvements in recent times with their Gallium3D drivers
becoming mature across all generations and support for new features
(such as DRI2 page-flipping) landing in the mainline code and beginning
to make its way to users. The time required to bring up support for new
generations has also been reduced greatly and with the Radeon HD 8000
series there should be a turning point for their open-source strategy.
In this article, we are providing an updated look at the course of the
open-source driver's performance for the past two years."