How Long to Cook Prime Rib?

Prime Rib is a beautiful dish to serve your guest or family. How long to cook your prime rib is depends on how large the cut of meat. A standard 4-rib cut, 9 to 10 lbs., will sear at 450 degrees for 15 minutes, then continue to roast for 1 1/2 to 2 hours at 325 degrees. The internal temperature should reach 120 degrees, or rare.