Beginning with the QGears2 Gears test using the X Render back-end, the proprietary Catalyst 10.4 driver is faster than the open-source ATI driver stack with the Radeon HD 4650, but it is slower with the new ATI 2D Acceleration Architecture. The frame-rate in this synthetic 2D test actually dropped by 20% with this newest ATI Catalyst Linux driver.
With the text test, the open-source ATI driver stack absolutely slaughters the performance of the proprietary Catalyst driver regardless of their new or old 2D acceleration paths. With the Catalyst 10.6 driver, however, the measured frame-rate drops by 40% compared to the Catalyst 10.4 release.
The X Render performance drops again with Catalyst 10.6 when compared to Catalyst 10.4, but in this image scaling test it still puts its numbers ahead of the open-source ATI Linux driver in Ubuntu 10.04 LTS.