The cooling of multiple tiny heatsinks isnt even especially on the s9’s since they r often put on at varyin angles making airflow harder. Some chips will get more cooling than others. With a solid one the fins would be in a perfectly straight row and it would have the added bonus of transferin heat from other chips that r hotter to chips that are running cooler. It doesnt allow the density like sidehack mentioned and im not sure ne one likes the epoxy idea. I liked the old screw and tension spring method but they get paid the big bucks to design these things not me. Even so many do agree about the epoxy part lol.