How to go fast(er/est) on a snowboard?

Im 17 and ive been snowbaording for 6 yrs now. Im not big on tricks and love to go fast. Usually im one of the fastest SNOWBOARDERS on the mountain. but my best friend skiis, every now and again we race. he usually beats me because skiis are inherently faster than a snowboard. Is there anything i can do to change this? (tips to ride faster)