15 is quite correct, definitely not horrible, so don't worry too much about that. It's not a rating, more a way to compare how browsers and hardware improve ove

15 is quite correct, definitely not horrible, so don't worry too much about that. It's not a rating, more a way to compare how browsers and hardware improve over time. The scale goes up to 140 so that there's some space for software improvements as well as future hardware.