What's the difference between DDR$3$ and DDR$3$L$?$

DDR$3$L requires less power than DDR$3$

DDR$3$L is faster than DDR$3$

DDR$3$L has the same number of pins as DDR$4,$ not DDR$3$

DDR$3$L is smaller than DDR$3$ so it can fit into smaller cases