For those ATI/AMD customers with graphics cards of the Radeon HD 2000/3000/4000 generations, they are supported by the "Catalyst Legacy" driver but this older proprietary driver branch is seldom updated for new Linux kernel and X.Org Server releases. Thus, the only real option for those with these older Radeon GPUs is to use the open-source Radeon Gallium3D graphics driver. But how does this driver compare to the still-maintained Catalyst Legacy driver for Windows 8? Here are some benchmarks.
Having a clean Windows 8 Pro x64 install for doing the recent Intel Haswell Windows vs. Linux benchmarks, I then proceeded to run similar Windows 8 vs. Ubuntu Linux OpenGL graphics comparisons on NVIDIA GeForce and AMD Radeon GPUs, which will be published in forthcoming articles on Phoronix. On the AMD side I did HD 5000/6000/7000 series graphics card benchmarks on Catalyst and the open-source driver, but then also decided to do some legacy tests.
AMD maintains the Catalyst Legacy driver for HD 2000/3000/4000 series graphics cards with Windows 8 support. The most recent release is Catalyst Legacy 13.4 Beta, which fortunately works with an updated Windows installation thanks to a stable driver ABI on Windows. On Linux the Catalyst Legacy driver doesn't work with an updated Linux install but the users are left to rely on the open-source driver. So there for this ATI RV770 testing I used the very latest open-source driver stack.
From Ubuntu 13.10 with all available updates as of this week, a Linux 3.11 Git kernel was installed plus Mesa 9.2-devel Git. The Linux 3.11 kernel was booted with Radeon dynamic power management is enabled. This represents the very latest look possible for the open-source Radeon Gallium3D R600 driver. A second run was done as well when enabling the R600 SB shader optimization back-end, which is a non-default setting but can dramatically boost the driver's performance. These Linux numbers were then compared to Windows 8 Pro x64 on the same system with the Sapphire Radeon HD 4870 512MB graphics card.
Benchmarking under Linux and Windows was handled in an automated and reproducible manner using the open-source Phoronix Test Suite software. Benchmarks from more recent AMD Radeon GPUs on the mainline Catalyst driver will come out in the next few days on Phoronix.