Some "Correct" translations quotes and tidbits taken from B3d:
Unreal Engine 5 running on PS5
forum.beyond3d.com
-The Epic guy is saying the first scene(Lumen) can run at 40fps on his notebook, not the whole demo.
-If its a 1080P screen, 2 triangle per pixel, make some compression on vertex, than you still can run this demo, no need very high bandwidth and IO like PS5.
-UE4.25 implemented asynchronous/overlapped loading (Because bottleneck was the CPU). They overhauled their shaders to work well with the event-driven loader. This gave them >50% loading speed improvement.
-In the final UE5 scene, compression and careful disk layout avoided the need for high speed SSD. The workload wasn't that high.
-Guy mentioned they can run the demo in the editor at 40fps, not 40+ but did not specify resolution.
-Currently Nanite has some limitations such as only works on static meshes, doesn't support deformation for animation, doesn't support skinned character model, supports opaque material but no mask.
-Lumen costs quite a bit more than Nanite.UE5 could eventually be a hybrid renderer using both Lumen and Raytracing in the future.