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Difference between SRAM and DRAM

01 Feb 2019 6:38 am || 0

RAM or Random Access Memory is of two types - DRAM (Dynamic RAM) and SRAM (Static RAM). These two types of RAM are useful for holding data, but they do so in their ways. The pros and cons of using DRAM and SRAM are also quite diverse, given their many points of difference. For instance, for data to be retained effectively in DRAM, it has to be refreshed periodically. This is not the case in SRAM as the transistors placed inside it continues to hold data until the power supply is cut off.

The speed, functionality, performance and features of these two kinds of RAM can be understood by going through the points of difference between static and dynamic ram. This article aims to discuss the main difference between SRAM and dram, the definitions of static ram and dynamic ram, etc. in a simple way. It will help those preparing interview questions to know sram and dram difference as well. Read on for more.

SRAM vs DRAM

Basis of difference DRAM SRAM
Definition Dynamic random-access memory refers to a type of random-access memory that provides storage for every bit of data within a different capacitor in any given integrated circuit. Static random-access memory refers to a specific type of semiconductor memory. It utilizes bistable latching circuitry for the cause of storing every bit of data. It is static and need not be refreshed periodically for its performance.
General applications The DRAM is mainly found as the main memory in computers (e.g. DDR3). It is not recommended for long-term storage. L2 and L3 cache units in a CPU are the general areas of application of an SRAM.
Typical size 1GB to 2GB DRAM is commonly found in smartphones and tablets. The DRAM capacity is 4GB to 16GB in most laptops. 1MB to 16MB is the storage capacity of SRAM.
Position where present The DRAM is placed on the motherboard. The SRAM can be found on the processor or lodged between the main memory and processor of a computing device.
Speed DRAM has the characteristics of off-chip memory. It has a more substantial access time than the SRAM and is therefore slower. SRAM is in the form of on-chip memory. It has a small access time, and thus it is faster than DRAM.
Storage capacity DRAM possesses a larger storage capacity. SRAM is usually of smaller size.
Cost-effectiveness The DRAM is reasonably priced. SRAM is expensive and is thus less cost-effective than DRAM.
Density The DRAM is highly dense. SRAM is rarer than DRAM in density.
Design construction The DRAM is simplistic in design and thus, easy to implement. As the number of transistors present in a memory module impacts its capacity, a DRAM module can showcase six times higher capacity than any SRAM module with the similar number of transistors. The construction and design of SRAM is complicated as it uses many different types of transistors for its performance.
Number of transistors DRAM requires a single transistor for forming a block of memory. A single block of memory in SRAM makes it necessary to include six transistors.
Nature of charge leakage The DRAM is dynamic as it utilizes a capacitor that produces leakage current. This is possible because of the presence of the dielectric present inside the capacitor. The dielectric is used for separating the conductive plates and fails to be a perfect insulator. This is the reason behind the DRAM requiring power refresh circuitry. SRAM does not face any issues of charge leakage.
Power Consumption Power consumption rate is higher in DRAM in comparison to SRAM. SRAM performs on the principles related to the changing of the current’s direction through switches. It does not hold charges like DRAM.
Simplicity DRAMS are more complex in comparison to SRAMs. SRAM modules are more straightforward compared to DRAM modules. Easy-to-build interfaces can be developed to access the memory.

What is SRAM?

SRAM (full form of SRAM is Static Random Access Memory) uses six transistors and is manufactured using the CMOS technology. The construction of SRAM comprises of two additional transistors that are responsible for access control. It also consists of two cross-coupled inverters. These inverters are utilized to store binary type data. SRAM is comparatively speedier than DRAM. As it consumes less power, it serves as a more cost-effective alternative for the sake of memory storage. The SRAM can hold data only along as power supply is available to it.

Read here Difference between RAM and ROM

What is DRAM?

DRAM (full form of dram is Dynamic Random Access Memory) refers to a kind of RAM that comprises of transistors and capacitors. The capacitors in DRAM are used for data storage wherein the value of one in a bit showcases that the capacitor is charged. A discharged capacitor depicts a value of zero. As capacitors tend to get discharged, they are responsible for charge leakage in DRAMs.

DRAM has higher power consumption as it continuously leaks charge even when continuous power is supplied to it. This is the reason why this type of RAM is termed as dynamic. To retain data for more extended periods, a DRAM has to be repeatedly refreshed with the help of additional refresh circuitry. The DRAM is cheaper in comparison to SRAM and is usually available with higher memory storage capacity. Dram needs just one transistor for the creation of a single block of memory.

Key difference between Static and Dynamic RAM

  • When we compare sram and dram, the main difference that surfaces is for their speed. Because SRAM has no requirement of refreshing itself, it is faster than DRAM. The average access time attributed to DRAM is 60 nanoseconds approximately, while SRAM offers access times that’s as low as ten nanoseconds.
  • SRAM requires more transistors in comparison to DRAM for the sake of storing any specific amount of data. The DRAM module needs just one transistor and a singular capacitor for storing each bit of data. On the other hand, the SRAM requires six transistors. As the total number of transistors present in any memory module would determine its capacity, DRAM modules are known to have six times higher capacity than SRAM modules, given that they have the same number of transistors.
  • As far as pricing is concerned, SRAM serves to be far more expensive than DRAM. 1 GB of SRAM cache would cost around $5000, on the other hand, 1 GB DRAM can be purchased for $20-$75.

Conclusion

The DRAM is derived from SRAM and has been effectively designed to handle the challenges and issues of SRAM. However, DRAM is less speedy than SRAM and boasts of higher power consumption. As it is prone to charge leakage, it needs to be refreshed very frequently for retaining its charge. The knowledge about the difference between dynamic ram and static ram helps users apply them carefully and as per their needs. In case you have any further queries or inputs concerning what is a dram, what is SRAM, the difference between dram and SRAM, the definitions of SRAM and dram, etc. then do write to us; we will be glad to hear from you!