Question: how long does it take to cook a prime rib at 225?
Answer: How Long to Smoke a Prime Rib? Plan 35 minutes per pound at 225 degrees F for smoking a rare roast. 40 minutes per pound at 225 degrees F for smoking a medium roast. Don't forget to allow at least 30 minutes of rest time and another 15 minutes or so for the high heat sear before serving.