EDO (Extended Data Out) memory was introduced in 1995 as a successor to Fast Page Mode (FPM) memory. It was the first memory type to allow the CPU to access data while still waiting for the previous data to be transferred. This was achieved by keeping the data bus active during the read cycle, which allowed the CPU to fetch the next piece of data without waiting for the current data transfer to finish.

DDR (Double Data Rate) memory was introduced in 2000 as the successor to SDRAM. DDR memory uses a technique called “double pumping” to transfer data twice per clock cycle, effectively doubling the memory’s data transfer rate. This allowed for faster data transfer speeds and better system performance compared to SDRAM.

Today, DDR memory is the most common type of memory used in computers and other electronic devices, with DDR5 being the latest iteration.