What does "DDR" stand for in RAM terminology?

The term "DDR" in RAM terminology stands for Double Data Rate. This designates a type of Synchronous Dynamic Random Access Memory (SDRAM) that can transfer data twice per clock cycle. In other words, while traditional single data rate (SDR) memory only transmits data once per clock cycle, DDR memory takes advantage of both the rising and falling edges of the clock signal to send data, effectively doubling the data transfer rate without increasing the clock frequency. This efficiency leads to improved performance and faster speeds in memory operations, which is essential for high-performance computing tasks.

DDR has multiple generations, including DDR2, DDR3, DDR4, and DDR5, each offering enhancements in speed and bandwidth over the previous generation, but all maintaining the fundamental principle of double data transmission.