Yes, size of brain of all humans have same size, Einstein used it more .To Be true Almost 30–39% was only used by Sir,Einstein and Considering our selves We just use about 10-15% of the Brain. Just Imagine our DNA where there are molecules and Chemical Formulas Who’s uses are still not been defined and Till Now we are just using our Brain to Perform very Common and Basic Tasks and the Use of 6th sense is also very less. When our Brain Functions To 100% we wouldn’t Still be the Humans we would be Aliens (or) we would Just be Genius!!