The fastest graphics cards at the moment all belong to NVIDIA. We’re not saying AMD has nothing compelling to offer gamers, but when it comes to the best of the best (and 4K gaming), right now it is pretty much Pascal or bust. That will change once Vega arrives, which we anticipate will bring parity with Nvidia’s GeForce GTX 1070 and higher

Source: Hot Hardware – AMD Radeon RX Vega 3DMark TimeSpy Benchmark Allegedly Leaks