Maybe the slowness is more due to poor high level design for the problem (& if you want an highly optimized result)? E.g. AoS everywhere instead of SoA if neede

Maybe the slowness is more due to poor high level design for the problem (& if you want an highly optimized result)? E.g. AoS everywhere instead of SoA if needed. I don't know I have not checked the source code, but it is a possibility.