Switching to the QGears2 test that is written with a Qt4 interface, we used the X Render back-end for these 2D tests. The "gears" performance with the X Render back-end was faster on the X1950PRO when using the open-source ATI driver. The xf86-video-ati driver allowed for an average of 93.87 frames per second while the Catalyst 9.2 driver was positioned at 82.40 frames per second.
The gears test is not the only area where the X Render back-end is slower on ATI's proprietary Linux driver. Using the QGears2 text test, the margin was even larger: 109 FPS vs. 132 FPS.