What is the Difference Between Similar But Different Things, Terms, and Objects

What is the Difference between DDR1, DDR2 and DDR3

DDR or Double Data Rate is a type of computer RAM (Random Access Memory) that is categorized as a fastest memory. No doubt, the architecture of DDR RAM is same as like SDRAM. However, the data transfer rate in case of DDR RAM is much faster as compared to SDRAM.