Just a quick first test:
In Epic quality, differences in GI are huge:
UE5.3:
UE5.4 Preview 1:
(Yeah, a little performance drop in 5.4, but in the other hand reflections are slightly better).
When changing booth to Cinematic, they look almost the same, in the right way.
Also noticed that Lumen with r.Lumen.Reflections.Temporal = 0 is much more worse in 5.4. (And yes, disabling temporal accumulation for reflections can be an actual use-case, as it can achieve better results, just combining it with other cvars and parameters to reduce the noise. In fact, if I’m not wrong, we will need to disable it if we want to use DLSS ray reconstruction). First, UE5.3; secondly, UE5.4:
Off-topic: the edge’s artifacts are still there, as nobody knows who is the responsible of this area of development (RT shadows):
