Well as for plain on optimization we have the use of a bunch of ISPC to several system including Math, Animations, skeletal meshes, etc. While it’s true that 4.25 already had ISPC incorporated. More systems have been moved to ISPC since them.
I wanted to check quickly how chaos was affecting performance by testing the project on 4.2x Chaos but just found out that the Chaos Engine versions of UE4 were removed from the launcher. Will have to download the source to check how it goes.
Hopefully will do it later today just after I get some crucial work done.