Did a quick test, and the conclusion is: dont use 5.3, it actually performs significantly worse than 5.2, which already performs worse than 5.0 does for me.
Here are my results, same project, same savegame, same settings, same everything:
Explanation:
- Nanite Only = No VSM (CSM instead), Lumen off, everything to lowest settings and TSR disabled.)
- VSM only = Nanite + VSM (since I cant disable nanite it would screw performance completely)
- Lumen Only = Nanite + Lumen (see above)
- Maxed out = Nanite + Lumen + VSM + TSR and everything else turned up as high as the game allows it.
As is clearly visible, 5.3 is slower when GPU bound.
Visually speaking, there are tiny differences visible, like better shadows on far away leaves and slightly brighter Lumen, but thats it.
PS: Yes, I am aware that Lumen doesnt play nice with some trees… working on it, its painful. (You either get dark trees (5.0 and 5.1) or you get this… 5.2+)
Looking at these numbers… I will stick with 5.2 for the foreseeable future, until at least the next GPU generation.
Performance wise I could “afford” to go from 5.0 to 5.2 despite some lost frames here and there, but 5.3 is another 10% that just goes “poof”. I already have a hard time to reach the same performance I had in 5.0 in 5.2, so 5.3 is out of question.
I do not use Nanite for everything, because I dont want to load even more onto low end gpus, that can otherwise be dealt with by the CPU, so the game is mixed use and turning even more nanite-stuff on has a negative impact on performance.
With 5.3 I am running out of Ideas how to claw back performance, if it gets thrown out of the window like this. (I have not yet fully recovered from 5.0 → 5.2… 
)
As much as I like the improvements and progress, -10% fps is a hefty price for no (realistically) noticable visual impact. (especially since we have performance stagnation on the cheap Graphics cards…)