The best roast beef are cooked at low-ish temperatures for long times. The more heat you use, the faster the outer edge will dry out. If you want to make a beautiful roast beef that’s a medium-rare pink nearly all the way to the edge, you need to use low temperatures and a long time. Say… 10 to 12 hours, as this recipe suggests. (Mind you, you can do this in the oven, too.)
From a box sold in Columbiaville, Michigan.
Basic Beef Roast (Crock Pot)
3-4 lb. roast
salt, pepper, or other desired seasonings
Do not add any liquid. Cover. Cook on low 10-12 hours. High 4-5 hours.
And obviously, however you cook it, let the meat rest before you slice it. There’s a lot of debate on what the right amount of time is, but with a beef roast, where room temperature is where the flavor is probably best, I’d say you should err on the side of longer and wait 20 to 30 minutes.