AMD's Open-Source Radeon Driver After Four Years
The PCI-E X800XL 256MB graphics card was at 62% the speed of Catalyst for the Urban Terror game. The Radeon X1800XT graphics card was running at 90% the speed of Catalyst for this not-too-graphically-rich open-source game.
Switching over to another game engine, the Qfusion-powered Warsow game did not do as well with the current open-source code. The Radeon X800XL on the open-source code ran at 54% the speed of Catalyst 9.3. The Radeon X1800XT ran at 58% the speed of the binary blob.