I've heard the KS 120 REB is 1600 watts, but they have a soft start. How much watts do they draw with no load or light load?

They run around 700W to 800W at no load, full speed, and anything up to 1600W depending how hard you push it through the timber. With a good sharp blade, soft pine and slow feed rate draw is approx 900W to 1000W.