Which one should I buy DDR3 OR DDR3L
As I see on ELPIDA J4208EFBG-GNL-F datasheet, your current RAM is backward compatible for 1.5V :
Power supply: 1.35V (typ)
ó VDD = 1.283V to 1.45V
ó Backward compatible for VDD, VDDQ = 1.5V ± 0.075V
Take a good look at your mother board datasheet. It may not be for DDR3L.