Lightsmark is dreadfully slow with current Mesa / Gallium3D drivers compared to the proprietary AMD and NVIDIA drivers. The Catalyst driver was 4.75x faster than the Gallium3D driver and its 4.5 frames per second performance.
With VDrift, the Gallium3D driver was actually faster than Catalyst, but we have seen this out of the Radeon Gallium3D drivers (R300g and R600g) with other graphics processors and also with the Nouveau Gallium3D driver for NVIDIA GPUs. However, as noted earlier in this article, the Fusion support in VDrift is particularly flakey with many missing textures.
The performance relative to the Catalyst driver for the AMD Fusion E-350 under Linux is not too surprising. The proprietary drivers under Linux whether it is for AMD or NVIDIA hardware are the only serious choice at this point if needing maximum performance, features, and stability. Besides many of the Linux-native OpenGL games being able to run well on the Fusion hardware, the other poor point for the E-350 is the problems noted at the beginning of this article with several games not working and other issues. This is with the current Linux 2.6.39 and Mesa 7.11-devel code. Hopefully by the time of Ubuntu 11.10, Fedora 16, etc, these issues will be all cleaned up and we'll see better-optimized open-source drivers, but that already will be nearly a year after the E-350 first began shipping and there will almost certainly be new Fusion hardware to support at that point.
Today's benchmarking results can also be found on OpenBenchmarking.org for reference and running your own comparisons.