Counting In 1/4 Notes And 1/8th Notes
As I've mentioned in the past, the stumbling block to playing fast really has nothing to do with your fingers and their ability to move.
In fact, in my experience it has much more to do with your ear's ability to subdivide the beat and instruct the brain on when to tell the fingers to move... nothing to do with the actual moving.
The first step in correcting that is to learn how to subdivide beats better so your ear can become a stronger player in this game. Watch this video and try to do it too.