Quick Oats: the most processed and thinner than other oats. More of a mushy texture and cook the fastest. Old Fashioned Oats: Also called rolled oats, they have gone through a steaming and flattening process. Softer texture and take about 5 minutes to cook. Steel Cut Oats: closest to an unprocessed oat groat. They have a more coarse, chewy texture and take about 20 minutes to cook.