This is a set of electronic components that let all the parts of a computer communicate properly.
As companies like Intel come out with new CPU technology, they require new motherboard chipsets. The generation of RAM used with a computer is closely tied to the development of processors and motherboards. But you might wonder where DDR2 and DDR3 came from, and why they emerged. This isn't out of the ordinary, since many computing standards evolve over time. These are all future generations of the same technology with faster speed and other improvements, and are all the same physical size. Original DDR RAM was superseded by DDR2, DDR3, and now DDR4.