8x is the speed that the drive will right and Dual-Layer means that it can encrypt data onto 2 layers on the disk meaning it can hold twice as much data in the same space
8x is the speed that the drive will right and Dual-Layer means that it can encrypt data onto 2 layers on the disk meaning it can hold twice as much data in the same space
They are the same thing. 8x and dual layer are not mutually exclusive. *x is the speed and dual layer specifies that it can handle dual layer discs. An 8x Superdrive can burn DVDs at 8x AND burn dual layer DVDs as well.