22-Way AMD/NVIDIA OpenCL Linux Benchmarks To Start Off 2015
NVIDIA's GTX 970/980 dominate the competition. On a performance-per-Watt basis, the GTX 970/980 are even more compelling as shown in many Phoronix articles.
Hopefully these numbers are useful to you... Or that you run your own comparison via phoronix-test-suite benchmark 1501168-DE-LUXMARKCO88 to see how your system compares to these reference numbers.