Valve's ACO Helps Put New Life Into Radeon GCN 1.0 GPUs With ~9% Better Linux Gaming Performance

Among many other Valve ACO back-end improvements for Mesa 20.0, one of the notable additions is this AMDGPU LLVM alternative now working for Radeon "Southern Islands" / GCN 1.0 graphics cards. With this, these original AMD GCN graphics cards may have some extra life out of Linux gaming boxes thanks to slightly higher performance some eight years after these graphics cards first launched in the Radeon HD 7000 series.

ACO is the back-end to the Mesa Radeon Vulkan driver that's funded by Valve and optimized for speedy shader compilation to help with game load times and for delivering optimal gaming performance. With the upcoming Mesa 20.0, ACO works from the Radeon GFX10/Navi graphics cards back through the GCN 1.0 products. Granted, by default the Radeon DRM kernel driver is used for these graphics cards so you need to first boot the system with "amdgpu.si_support=1 radeon.si_support=0" for enabling the AMDGPU kernel driver that is needed for allowing RADV to work at all.

With Mesa 20.0, RADV ACO isn't enabled by default but requires the RADV_PERFTEST=aco environment variable. Using a Mesa 20.0-devel snapshot from today and testing with a Radeon HD 7950 graphics card, I compared the default and ACO-optimized performance on this graphics card. A range of Linux gaming Vulkan-powered benchmarks were run via the Phoronix Test Suite.