Just leaving some notes here.
I made some other tests with the base FPS template (c++). My results here are only on barebones projects. So they are just indicative or baseline performance. Im using same settings/project across ue4/5 versions
UE 4.27 physx V 4.27 Chaos
When comparing just regular performance (no physics simulation), I was surprised to see there was only a very minor difference in favor to physx.
My conclusion from this is that the major base performance drops are mostly related to 2 things.
Ticking system → Ticks have gotten around 30% more expensive in Unreal Engine 5, apparently because now the engine tries to have more control over tick execution.
Renderer ->After looking more into how Unreal handles rendering I realized that several changes had to be made for how meshes’s proxies are renderer for them to work with raytracing / nanite. This is a change that unescapable even by turning off lumen/nanite.
Material System → Likely, more the material system does more shader permutations because of lumen support
In other minor findings, I found that barebones ue 5.1 projects would perform slightly better than 5.4 projects. (although this changes with regularly sized project)
To go the point the difference in performance between 4.27(chaos) and 5.0 is the following on the ue4 fps template:
4.27 Base 850fps up to max engine fps (1250)
5.0 Base 490fps up to 780fps
I tried to reduce UE5 rendering settings as much as possible and this was the max fps I was able to get. The difference is big indeed.