Looking at the results of this test it seems like the first sentence of the conclusion is contradicting what is shown on the charts, here are some examples:
As you can see above all DX12 games show that Ryzen performs much closer to 7700K when paired with RX480.
To better ilustrate my point here is a graph with average excluding AoTS:E as it has negative scaling (Ryzen is faster):
As you can see from the average 7700K is 20,73% faster than Ryzen when paired with GTX 1060 in DX12 titles but only 5,89% faster than Ryzen when paired with RX480.
So looking at techreport article's title (Does Ryzen perform better with AMD GPUs?) we can answer like this:
Ryzen does compare better to 7700K in DX12 titles when paired with AMD GPU.
But instead author writes in first paragraph of the conclusion:
He did not find any evidence? This is clearly contradicting with presented data. There is some evidence showing that there are limitations when we pair Ryzen with Nvidia GPU. Its not decisive, but its there.
I am not saying that we should sharpen our pitchforks or start putting our tinfoil hats on. I am saying that reviewers should clearly rethink their testing procedures when reviewing Zen based cores in the future.