The Xonotic results varied but overall the Linux frame-rate with its Catalyst 14.4 driver was slightly higher than the Windows 8.1 scores. Our other common Linux OpenGL benchmarks were among the casualties of the Windows Catalyst 14.4 driver with the R9 290 and its stability issues.
Overall, these results are quite interesting for the Radeon R9 290 given its troublesome past under Linux. With Catalyst 14.4, the R9 290 series Linux situation appears a bit better, at least relative to the Windows performance, but we'll need to compare it against NVIDIA's latest hardware on their top-notch proprietary driver to see if the results are still disproportional on that front as we have seen in the past.
In terms of the AMD R9 290 series open-source RadeonSI driver support, that is still being worked on and it's not clear when the open-source Linux GPU support for these highest-end AMD graphics processors will be in good shape for those not wanting to use the Catalyst driver. Right now it's a problem getting any 3D/OpenGL applications working right on the R9 290 with Linux 3.15 and Mesa 10.3 Git.
Stay tuned for the other AMD, Intel, and NVIDIA multi-platform OpenGL tests in the week ahead. If you appreciate this extensive testing you can only find done at Phoronix, please consider subscribing to Phoronix Premium or making a PayPal tip; besides being time and resource intensive to carry out all of this Linux OpenGL testing, on the AMD side we end up having to buy our own high-end graphics cards as no high-end Radeon GPUs have been supplied by AMD in years to Phoronix.