Double data rate

A comparison between single data rate, double data rate, and quad data rate. The dots are where data transfers take place, measured in millions of transfers per second (MT/s).

In computing, double data rate (DDR) describes a computer bus that transfers data on both the rising and falling edges of the clock signal and hence doubles the memory bandwidth by transferring data twice per clock cycle. This is also known as double pumped, dual-pumped, and double transition. The term toggle mode is used in the context of NAND flash memory.