@sebastianlague has an excellent video up showing the impact of BVH (including SAH) on ray tracing performance. Good stuff.
https://youtube.com/watch?v=C1H4zIiCOaI
And thanks for the references to the BVH tutorial on my blog! https://jacco.ompf2.com/2022/04/13/how-to-build-a-bvh-part-1-basics/