He didn't say it was DXR, he said is was RT. Anyone can do RT, it's not a new concept and there are many ways to do it. What was being said is that RTRT is not exclusive to NVidia as has been shown possible on non-RTX platforms with Crytek's demo, which are in fact very good!
Fair point, the performance bracket of Navi is known, the chiplet nature of PS 5 is expected.
They openly stated zen 2 chips and, Amd would be best served to use the exact same chiplet for the cpu as everything else.
It requires an interposer and an io chip (which could be the console specific bit as that's logical lego based chip design) and a Gpu.
Why would the ps5 use a different Navi to the consumer pc space.
It doesn't make sense, it's going to be slightly different in memory architecture and possibly specs but the performance targets for Navi have been known for two years at least , Vega 64 at mainstream pricing.
And they'll be using RPM over specific compute hardware for rays so the change's in Gcn won't be too major i wouldn't imagine.
They've been working on the Gcn replacement but that is not Navi.