So, the game runs at 900p on Pro when outputting at 1080p and using the games resolution mode. This makes performance very stable, rock solid 30fps like the regular PS4, but also means it's running at a lower res.
It's the pinned comment from their analysis which I just watched
PS4 renders at a native resolution of 1920x1080.
PS4 Pro in the performance mode renders at a native resolution of 1920x1080.
PS4 Pro when outputting at 2160p in the resolution mode renders at a native resolution of 3200x1800.
PS4 Pro when outputting at 1080p in the resolution mode currently renders at a native resolution of 1600x900. Note that this mode seems to run at a solid 30fps like the base PS4.
I still don't understand why Tom is doing anything on DF, he never tests the Pro at 1080p output and it always leads to missing out on curious stuff.