When reading this morning of "double or quadruple the framerates that I got with RC1" for an R9 Fury owned by a Phoronix reader, I immediately set out to run some R9 Fury benchmarks on Linux 4.5-rc2 compared to my 4.5-rc1 results last week and compared to Catalyst. I also did the same for an R9 285 Tonga on AMDGPU as well for reference purposes.
Sadly, the performance didn't improve at all in my conditions for Linux 4.5-rc2 with the R9 Fury nor with the R9 285 (but at least with the R9 285, it's been performing well already compared to Catalyst speeds). Yes, PowerPlay was enabled. Yes, the latest firmware files were used.
The R9 Fury also still failed with Unigine Valley and Xonotic with image quality settings.
You can dig through all of the R9 Fury AMDGPU results via this new OpenBenchmarking.org result file.