Difference Between SRAM and DRAM



In a computer system, memory devices are used to store data and information. Computer memories are mainly classified into three types – primary memory, secondary memory, and cache memory. The primary memory is further classified into two types namely – RAM and ROM, where RAM is further subdivided into two types, i.e., SRAM and DRAM.

Read through this article to find out how an SRAM is different from a DRAM.

What is RAM?

RAM stands for Random Access Memory. It is the internal memory of the CPU for storing data, program, and program result. It is a read/write memory which stores data until the computer is working. As soon as the computer is switched off, data is erased. Therefore, RAM is a volatile memory.

What is SRAM?

SRAM stands for Static Random Access Memory. Each memory cell of SRAM is made up of a flip-flop, a 1-bit storage device. SRAM uses a matrix of 6 transistors. In this memory circuit, capacitors are not used. Thus, in SRAM, there is no data leakage, so SRAM need not be refreshed regularly.

SRAM is a high speed random access memory which is used in special applications such as cache memory in computers and other embedded systems. However, SRAM is relatively expensive because it uses comparatively more number of chips that increase its manufacturing cost. SRAM is a volatile memory which means it retains the stored data as long as the power is supplied to the computer.

What is DRAM?

DRAM stands for Dynamic Random Access Memory. Each memory cell of DRAM is made up of one transistor and one capacitor. In DRAM, the data and information is stored in the form of an electric charged on the capacitor. Since capacitor loses its data (charge), thus DRAM must be continually refreshed several hundred times per second to maintain the data.

DRAM is a small sized and less expensive type of RAM. For this reason, it is used as RAM in most computer systems. However, DRAM is relatively slower and has a short data life than SRAM.

Difference between SRAM and DRAM

Both SRAM and DRAM are the types of random access memory. Although, they are quite different from each other. The important differences between SRAM and DRAM are highlighted in the following table −

Parameter SRAM DRAM
Full Form SRAM stands for Static Random Access Memory. DRAM stands for Dynamic Random Access Memory.
Component SRAM stores information with the help of transistors. DRAM stores data using capacitors.
Need to Refresh In SRAM, capacitors are not used which means refresh is not needed. In DRAM, contents of a capacitor need to be refreshed periodically.
Speed SRAM provides faster speed of data read/write. DRAM provides slower speed of data read/write.
Power Consumption SRAM consumes more power. DRAM consumes less power.
Data Life SRAM has long data life. DRAM has short data life.
Cost SRAM are expensive. DRAM are less expensive.
Density SRAM is a low density device. DRAM is a high density device.
Usage SRAMs are used as cache memory in computer and other computing devices. DRAMs are used as main memory in computer systems.

Conclusion

The most significant difference between SRAM and DRAM is that SRAM is made up of flip-flops (transistor based circuit to store data bits), while DRAM is made up of transistors and capacitors. SRAM is used in specialized applications such as cache memory of computer systems. On the other hand, DRAM is used as the main memory in most personal computers.


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