Phoronix has taken an in-depth look at progress on AMD's open source Radeon driver
, and declares 2014 to have been a good year. There are several pages with detailed benchmarks, but the upshot is overwhelmingly positive:
Across the board there's huge performance improvements to find out of the open-source AMD Linux graphics driver when comparing the state at the end of 2013 to the current code at the end of this year. The performance improvements and new features presented (among them are OpenMAX / AMD video encode, UVD for older AMD GPUs, various new OpenGL extensions, continued work on OpenCL, power management improvements, and the start of open-source HSA) has been nothing short of incredible. Most of the new work benefits the Radeon HD 7000 series and newer (GCN) GPUs the most but these tests showed the Radeon HD 6000 series still improving too. ... Coming up before the end of the year will be a fresh comparison of these open-source Radeon driver results compared to the newest proprietary AMD Catalyst Linux graphics driver.