It seems you misunderstand what sharing resources means. As I have said above, both AMD and NVIDIA RT cores are fixed function units within a larger group of other units that comprise the AMD CU and NVIDIA SM. For example Texture Units (TMUs) are fixed function hardware doing only texture calculations, same is true for the RT Cores, they only do RT calculations (BVH etc). What sharing resources means is that the RT cores can have access and use resources that for example Texture units also need and use. If you go back to the AMD CU picture I have posted above, you will see that there is a Shared Memory inside the CU, so both RT cores and TMU units and others can have access and share resources with each other. BUT that doesnt mean that RT cores or TMU units are not fixed function hardware, it means that the architecture is such that both units within the CU can share resources with each other so that they can perform faster.