3DMark Fire Strike is a showcase DirectX 11 benchmark designed for today's high-performance gaming PCs. It is our most ambitious and technical benchmark ever, featuring real-time graphics rendered with detail and complexity far beyond what is found in other benchmarks and games today.
3DMark provides a reasonable indication of 3D performance, the GTX 1060 is a little bit faster than an R9 390 OC – meaning it's about equivalent to a stock R9 390X.
The gap between the GTX 1070 is, however, quite significant – about 40%, which you would expect given the substantial price difference.