The torque is the bit's cutting force, and this relates to a router's ability to cut various types of wood. Softwoods do not require as much torque as hardwoods. As for RPM, a machine set at 10,000 RPM will have a shaft that runs at the same speed. The bit you add to the shaft will also rotate at 10,000 RPM. However, the exterior edge of the bit will move at extremely high speeds, so if you're using a large bit, choose a router with a low RPM range.