3DMark, Unigine Heaven
Let's look at a set of tests from more standard benchmarks like Unigine Heaven and 3DMark.
I consider these tests to be somewhat of a "best case" for all the cards in our comparison. We aren't using our frame capture system, we aren't measuring frame latency, nothing like that; I think this should give you an idea of graphics performance if each vendor had the best result for each game.
Our 3DMark testing puts the GTX 1070 Ti just slightly ahead of the Radeon RX Vega 56 from AMD, and closer to the performance of the GTX 1080 than the GTX 1070. Obviously the NVIDIA to NVIDIA scaling seems reasonable, but as we saw in our gaming tests on the previous page, the GTX 1070 Ti is able to compete much more handily with the RX Vega 64 than AMD would like.
In Unigine Heave, the GTX 1070 Ti is only 1-2% slower than the GTX 1080!