What is the drying time difference between fast dry and normal polyurethane?

Hello. The drying time of Fast-Drying Polyurethane is 24 hours, before light use. We can't answer the second part of your question, as we offer various polyurethanes with varying dry times. We would need to know which specific polyurethane products of ours you are referring to. We cannot comment on the drying times of other company's polyurethane products. So that we can better assist you with this matter, please contact us directly at askminwax@sherwin.com or by phone at 1-800-523-9299. Regards, Minwax Customer Support