What came before ddr memory?

Before DDR (Double Data Rate) memory, the predominant type of RAM was SDRAM (Synchronous Dynamic Random Access Memory). SDRAM operated at a single data rate, meaning it could only transfer data on one edge of the clock cycle. This limitation prompted the development of DDR memory, which allows for data transfers on both the rising and falling edges of the clock signal, effectively doubling the data rate. Prior to SDRAM, older memory types included EDO RAM (Extended Data Out RAM) and FPM RAM (Fast Page Mode RAM).