The prime rib (also called rib roast) or rib steaks are cut between ribs 6-12. They're both the same thing, When I've paid to have processing done I've always had to specify if I wanted the rib roast or steaks. When done as rib roasts, they're typically cut in half, so you end up with 4 rib roasts. I've also done half steaks and half roasts. Prime rib is just a name, it doesn't mean it's been graded as Prime. Carcasses are graded as "Prime", "Choice", etc..., not the individual cuts.