Alright been testing it out.
Effectively it's dark magic, it looks roughly the same in motion, I tested it from my couch and pc monitor.
It seems LOD and draw distance was also tweaked to lower settings, but it's just a nitpick, definitely worthy compromise to get 60 fps.
I'm not sure it holds 60 as well as the default performance mode, but overall it's great.
It looks super solid, Spider-man still has reflections. Even his helmet still has RT. The dynamic effects still show up in reflections, I'm pretty happy.
The IQ remains immaculate so it definitely either is higher than 1080p or they're using the best AA solution on the market.