Which characteristic distinguishes DDR SDRAM from SDRAM?

DDR SDRAM, which stands for Double Data Rate Synchronous Dynamic Random Access Memory, is distinguished from standard SDRAM by its ability to transfer data twice per clock cycle. This is a significant advancement in memory technology because it allows DDR SDRAM to effectively double the data transfer rate compared to SDRAM without increasing the clock frequency.

In standard SDRAM, data is transferred only once per clock cycle, meaning it can send out data at the speed defined by the clock. However, DDR achieves higher throughput by taking advantage of both the rising and falling edges of the clock signal to transfer data. This capability dramatically improves performance and efficiency, making DDR SDRAM a better choice for applications requiring higher memory bandwidth.

Other characteristics, such as operating voltage or storage capacity, do not address the fundamental difference in data transfer mechanics between these two types of memory.