It doesn't really matter. Nobody's doing rendering on CPUs.
I get that he's sticking to comparing CPU to CPU rendering to compare apples to apples, but that's like saying "My new buggy whip is amazing!" in a news article written in 1950.
Everyone is doing GPU based rendering. Pascal based GPUs are still (I believe) several times faster than even current mid-tier AMD desktop processors. Pascal is two generations behind current GPUs, which are several times faster than it is.
What will actually be relevant and interesting is how the M1X's full capabilities can be leveraged for rendering, and how that will compare against Ampere GPUs.