AMD does the same thing and so does Intel, this is for CPU's too. The yield on silicon has a probability that some transistors wont work, so they disable those

AMD does the same thing and so does Intel, this is for CPU's too. The yield on silicon has a probability that some transistors wont work, so they disable those cores and create lower end models. Sometimes, to meet demand they do just simply disable cores, as it's also cheaper to have one process. Tesla does the same thing as well with their cars, funny enough.