Double Data Rate (DDR) is a Synchronous DRAM technology offering increased memory bandwidth and performance while maintaining the reliability of a proven technology. DDR SDRAM allows applications to transfer data more efficiently than standard SDRAM and operates at extended temperatures likely to be found in many demanding environments.

(Double data rate synchronous dynamic random access memory) is a class of memory integrated circuit used in computers. It achieves nearly twice the bandwidth of the preceding [single data rate] SDRAM by double pumping (transferring data on the rising and falling edges of the clock signal) without increasing the clock frequency. With data being transferred 64 bits at a time, DDR SDRAM gives a transfer rate of (memory bus clock rate)  2 (for dual rate)  64 (number of bits transferred) / 8 (number of bits/byte). Thus with a bus frequency of 100 MHz, DDR SDRAM gives a maximum transfer rate of 1600 MB/s.

DDR memory speeds are available as below:

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