With R600g Now Supporting OpenGL 4.1, See How The Open-Source Performance Compares To AMD Catalyst
There are two reasons for doing some end-of-the-year Radeon R600 Gallium3D driver testing with pre-GCN graphics cards. First, since the pre-GCN (HD 6000 series and older) support is being dropped by the new Radeon Software driver. Secondly, the R600g open-source driver finally supports OpenGL 4.1 for select GPUs. In this article is a look at the AMD Catalyst Linux driver with the last official release for HD 6000 series hardware compared to the very latest open-source Radeon graphics stack on Ubuntu Linux with a variety of interesting OpenGL Linux game tests.
While some Phoronix readers have reported success using the Radeon Software Crimson Edition driver with pre-GCN hardware after making a few modifications, I decided to use the Catalyst 15.9 Linux driver as it was the last official release for this hardware. Additionally, it's what is currently shipped by Ubuntu 15.10 and other distributions so it's what most Linux gamers are utilizing. Beyond that, in my tests of Radeon Software Crimson, the performance didn't change much so these results would likely be the same anyhow.
On the open-source side, I was using Mesa 11.2-devel + LLVM 3.8 SVN via the Padoka PPA on Ubuntu 15.10. I was also using the Linux 4.4 Git kernel for the latest DRM support. Lastly, I manually enabled the DRI3 rendering support for greater performance.
The R600g-supported graphics cards I tested were the Radeon HD 6870 and Radeon HD 6950 as they are my highest-end pre-GCN hardware available. The Radeon HD 6950 did advertise OpenGL 4.1 support with the open-source graphics driver while the HD 6870 only has OpenGL 3.3. Right now the R600g driver only has OpenGL 4 support for the AMD Cayman (HD 6900) series and Cypress (HD 5800) series. With Catalyst, both graphics cards were advertising OpenGL 4.4 support.
The Linux OpenGL tests ran for this article included BioShock Infinite, Counter-Strike: Global Offensive, DiRT Showdown, Metro 2033 Redux, Metro Last Light Redux, Team Fortress 2, Tesseract, and Xonotic. Many of these titles explicitly need OpenGL 4 support and are only now able to run on this open-source Radeon R600 Gallium3D driver. All of the tests in this article were facilitated via the open-source Phoronix Test Suite. If you would like to support all of this testing work done at Phoronix.com, please consider trying out Phoronix Premium for supporting our work while enjoying ad-free viewing and seeing large articles (such as this piece) on a single page.