Digital Foundry made a video about it. Basically, you need a card that supports new rendering technologies that only started appearing on Nvidia cards after the GTX 10XX series (not sure for AMD). The game actually looks good on lower graphics. Putting everything on low won't make it look like a PS2 game. The path tracing will absolutely demolish your performance, though, but that's to be expected because it's insane to expect real-time path tracing to do anything else with the current hardware (think of their path tracing as a tech demo more than an actual feature).