Both treadmills have a 3.0HP motor that is Continuous Duty. Both treadmills have built-in speakers that allow you to plug in any MP3 player (like an iPod) and have it play aloud. The heart rate zone graph on the F83's console (a feature not shared with the F80) allows you to visually measure your heart rate, so that you can stay within the recommended zone while you work out. The F83 is an improvement over the lower cost F80 in that it has a larger running surface (20" x 58" compared to 20" x 55"), can go up to 12 mph (instead of just 11 mph) and has a reinforced framework (which makes for a higher user weight limit). However, the F83 lacks the larger 20" x 60" running surface, 33" x 80" deck, 400 pound user weight limit, and 3.5HP motor of the flagship F85 treadmill. The Sole F83 comes with a lifetime frame and motor warranty, a five year parts warranty, and a two year labor warranty.