What Is the Difference Between DRAM & SDRAM?

By Scott Friedman

Dynamic random access memory (DRAM) is a simple way to store data on a computer for a short period of time. Synchronous random access memory (SDRAM) is the same as DRAM except that regular DRAM is asynchronous. Synchronous random access memory stays synchronized with the computer's clock which allows greater efficiency in storing and retrieving data compared to asynchronous DRAM.


Dr. Robert Dennard invented DRAM in 1967 while working for IBM and received a patent for this groundbreaking technology in 1968. Known as the DRAM memory cell, Dennard's invention makes use of a single transistor that reads from and writes to a capacitor that stores data. Many innovations sprang from Dennard's single transistor memory cell technology, among them SDRAM which synchronized to the computer's clock thereby increasing efficiency when reading from or writing to the random access memory.


Previous forms of memory storage were as large as a room and required constant cooling. However, as memory storage technology advanced, these devices became smaller and cheaper. The invention of DRAM by Dr. Dennard enabled a large leap forward in making computer technology smaller, cheaper and therefore more accessible to the average consumer.

Types of Memory

There are several forms of memory storage such as DVDs, CDs, hard disks and read only memory (ROM), but random access memory (RAM) is a faster form of storage than most. That is why RAM is utilized as a kind of short term memory on your computer as oppose to a hard disk which would be comparable to long term memory. This short term memory is used to run the operating system and any applications you may use, but once you shut the computer down the RAM is wiped clean.

Function of DRAM

Dynamic random access memory utilizes one transistor to store data on one capacitor, but that capacitor will lose the data as it loses its charge unless the capacitor is periodically recharged. The recharging of the capacitors is the reason the word dynamic is used in dynamic random access memory. Once the capacitors no longer receive a charge, the data is lost. DRAM operates asynchronously with the computer's clock sending instructions as soon as it receives them from the user's interface instead of waiting to synchronize with the computer system's clock like SDRAM.

Features of SDRAM

SDRAM is synchronized with the computer's clock to allow it to send instructions more efficiently by joining a pipeline of other instructions the computer is processing. The pipelining of information in a computer allows it to receive another command before it has finished processing the previous command. This allows SDRAM to operate at much higher speeds, making it the most popular form of RAM offered on computers.