The time to render an image is O(k log n), but the space required for any given pixel is O(log n). A BVH search is a recursive operation. Each pixel needs its o

The time to render an image is O(k log n), but the space required for any given pixel is O(log n). A BVH search is a recursive operation. Each pixel needs its own stack. Rasterizing triangles requires O(1) space. So you can cram 4096 or whatever very, very dumb "cores" into a GPU that can rasterize, but if you want to spend the same amount of silicon to raytrace? Not so much.