Medium Well.....................................145 degrees
Well.................................145 degrees and above
Tips:
A good rule of thumb to remember for rare roast beef is to start with fresh meat and cook for 20 minutes per pound.
Roasting meats have what is called "carryover cooking." Roasts will continue to cook after they are removed from the oven, raising the internal temperature as much as 5 to 10 degrees. Keep this in mind when cooking roasts and always allow meat to stand 20 to 30 minutes before carving.
Recipe by Dewig Meats at https://dewigmeats.com/recipes-tips/boneless-prime-rib-roast/