I once worked in a restaurant on the coast that regularly sold four roast rib loins in a day. During the tourist season we would keep eight loins in our big oven around the clock.
We’d take the loins to rare. The carving station was set up under a heat lamp next to the grill, where the meat would continue to cook in service, so we rotated sections of meat on and off the carving board. If someone ordered prime rib well done—and, yes, such people do exist in this world—we’d drop a cut into the well of warm au jus we kept at the grill station until meat was grey and the tip and cap had peeled away from the eye. Smart customers who wanted a slice on the done side ordered an end piece.
Our menu called this beef dish prime rib, but we rarely used USDA Prime beef. We most often used a Choice rather than the much more expensive Prime grade, but rib roast is usually called prime on menus because it is, after all, from one of the eight prime cuts in a whole beef (brisket, shank, rib, loin, round, chuck, flank, and plate), so you can bet a rib roast is expensive. Bone-in roasts usually have three to seven ribs and are slightly more expensive.
For an evenly-cooked rib loin, pat the meat dry, brush with oil, and coat with sea salt and minced garlic. Place on a on a rack in a heavy pan and cover lightly with foil. Leave it out while you preheat the oven to 500. When the oven is hot, put the roast on a middle rack for a half hour, then turn the heat down to 250. In a couple of hours, begin checking with a thermometer. When you get a reading of 125 in the thickest part of the roast, immediately remove the meat from the oven, and let rest for a while before carving and serving.
