So that includes the 2000 series? And what is mega geometry?
It's a new api that basically extends ray tracing to support streaming triangle clusters, to be compatible with mesh shading and nanite. It also seems the bvh rebuilds are accelerated on the gpu with less cpu requirements. Not sure how it all works yet, but the intent is to fit detailed models into the bvh by streaming in clusters and not have a big cpu hit. So you won't have reflections that show simplified lods of objects etc. Not sure how well it'll work on older gpus, because the new RT cores on blackwell have support for cluster intersections, on top of triangles and box/volume intersections.