AFAICT it's not really different, they're just calling it something else for marketing reasons. The system described in the Sony patent (having a fixed-function unit traverse the BVH asynchronously from the shader cores) is more or less how Nvidia's RT cores worked from the beginning, as opposed to AMDs early attempts which accelerated certain intersection tests but still required the shader cores to drive the traversal loop.
AFAICT it's not really different, they're just calling it something else for marketing reasons. The system described in the Sony patent (having a fixed-function unit traverse the BVH asynchronously from the shader cores) is more or less how Nvidia's RT cores worked from the beginning, as opposed to AMDs early attempts which accelerated certain intersection tests but still required the shader cores to drive the traversal loop.