When I was working on this project, I was trying to restrict myself to the architecture of the original Ray Tracing in One Weekend book series. I am aware that things are not as SIMD friendly and that becomes a major bottle neck. While I am confident that an architectural change could yield a massive performance boost, it's something I don't want to spend my time on.

I think it's also more fun sometimes to take existing systems and to try to optimize them given whatever constraints exist. I've had to do that a lot in my day job already.