AMD Radeon R9 290 OpenGL On Ubuntu 15.04: Catalyst vs. RadeonSI Gallium3D
With Warsow the Catalyst driver had only an 11% frame-rate advantage on the R9 290 over the open-source driver.
With the Xonotic game, the Radeon R9 290 on RadeonSI Gallium3D did relatively well against Catalyst within about 10%.