Phoronix published a review on the 31-Way NVIDIA GeForce / AMD Radeon Linux OpenGL Comparison - End-Of-Year 2016

A quote from the article:

Last week I published some fresh AMD Linux 4.9 + Mesa 13.1-dev benchmarks on many different AMD Radeon GPUs going all the way back to the Radeon HD 4800 series days. Today those numbers are being complemented by an extensive NVIDIA GeForce Fermi / Kepler / Maxwell / Pascal comparison to make up a 31-way NVIDIA/AMD Linux OpenGL performance comparison. If you are curious how the NVIDIA and AMD Linux performance is with the very latest drivers and going back several hardware generations, this holiday article is for you.

As already mentioned, the testing on the AMD side was with their fully open-source driver stack and using the newest code (Linux 4.9 + Mesa 13.1-dev) where this mainline code continues to support all AMD GPUs, even going back to the RV770 days compared to AMDGPU-PRO now just supporting GCN hardware. Overall the open-source AMD Linux driver stack advanced a heck of a lot this year as covered in the many Phoronix articles. The AMD cards tested based upon what I had available and limiting it to the HD 4890 and newer were: the Radeon HD 4890, HD 5830, HD 6870, HD 6950, HD 7750, HD 7950, R7 260X, R9 270X, R9 285, R7 370, RX 460, RX 470, RX 480, and R9 Fury. On the FirePro side I was also able to test the V8750 and V8800 as additional data points but unfortunately have no newer FirePro / Radeon Pro hardware.

 31-Way NVIDIA GeForce / AMD Radeon Linux OpenGL Comparison - End-Of-Year 2016 @ Phoronix