Different Types of RAM

Types Of RAM

There are two types of integrated RAM chips:

1. SRAM (Static RAM)
2. DRAM (Dynamic RAM)

Also, see Types of Memory RAM and ROM 

Static RAM

SRAM is an abbreviation for static RAM. Data is saved in this form of RAM by utilizing the state of a six-transistor memory cell. Static RAM is mostly utilized as a cache memory for a CPU processor.

SRAM memories are made up of circuits that can store data for as long as power is given to them. This means that this form of memory requires continuous power.

Source: Static RAM

However, data is lost when the power goes off due to the volatile nature of the environment. SRAM chips employ a 6-transistor matrix with no capacitors. Because transistors do not need electricity to avoid leakage, SRAM does not need to be updated on a regular basis.

Advantages of SRAM

Here are some benefits /pros of utilizing SRAM:

• When it comes to speed, SRAM outperforms DRAM. It signifies that it operates more quickly.
• To develop a speed-sensitive cache, SRAM is employed.
• It uses a moderate amount of electricity.

Disadvantages of SRAM

Some of the drawbacks of using SRAM are:

• SRAM does not provide program refresh services.
• It has a limited amount of storage space.
• It is more expensive than DRAM.
• Since it is volatile, you will lose data if the memory is switched off.
• SRAM has a more complicated design.
• Lowers the memory density.

Dynamic RAM

DRAM refers to Dynamic Random Access Memory. It is a sort of RAM that allows each bit of data to be stored in a distinct capacitor within a specific integrated circuit. 

Dynamic RAM is a type of computer memory that is common in many current desktop computers.
 

Source: Dynamic RAM

This RAM is a volatile memory that must be refreshed with voltage on a regular basis. Otherwise, the data recorded on it is lost. DRAM stores binary information as electric charges applied to capacitors.

Advantages of DRAM

Here are some benefits/pros of utilizing DRAM:

• It has a larger capacity for storing. As a result, it is utilized to develop a system with more RAM space.
• It is not necessary to refresh the memory contents.
• Provides a straightforward framework.
• It is cheaper compared to SRAM.
• You don't have to refresh the memory contents, and it has a faster access time.
• Since logic or circuitry is required, the memory module itself is simplified.

Disadvantages of DRAM

Some of the drawbacks of using DRAM:

• When compared to SRAM, it consumes more power.
• When the power is turned off, you will lose data.
• Since it is slower than SRAM, it takes longer to access data or information.

Types Of DRAM

Majorly, DRAM is classified into five types:

 

1. Asynchronous DRAM (ADRAM)

In Asynchronous DRAM, the memory device's timing is managed asynchronously. 

To regulate the time, a dedicated memory controller circuit generates the appropriate control signals. The CPU must account for the memory's response time.

2. Synchronous DRAM (SDRAM)

The access speed of these RAM chips directly concurs with the CPU's clock. To do this, the memory chips must stay operational when the CPU wants them to be. 

These memories function without imposing wait states on the CPU-memory bus. SDRAM is commercially available in the form of modules that include numerous SDRAM chips to provide the requisite capacity for the modules.

3. Double-Data-Rate SDRAM (DDR SDRAM)

This faster type of SDRAM operates on both edges of the clock signal, whereas regular SDRAM operates only on the rising edge of the clock signal.

Since they send data on both clock edges, the data transmission rate is doubled. Memory cells are divided into two groups in order to access data at a rapid rate. Each group is accessible independently.

4. Rambus DRAM (RDRAM)

Over a limited CPU-memory interface, RDRAM delivers a very high data transfer rate. 

It employs a variety of speedup methods, including a synchronous memory interface, caching inside DRAM chips, and extremely rapid signal timing. The Rambus data bus is 8 or 9 bits wide.

5. Cache DRAM (CDRAM)

This memory is a form of DRAM memory that includes an on-chip cache memory (SRAM) that serves as a high-speed buffer for the main DRAM.

You can also read about the interleave memory and Open Source Operating System.

Difference between SRAM vs DRAM

SRAM	DRAM
SRAM requires a steady power source but uses less power.	Since the information is stored in the capacitor, DRAM consumes more power.
SRAM is more expensive than DRAM.	DRAM is less expensive than SRAM.
When compared to DRAM, SRAM has a shorter access time.	The access time of DRAM is higher. It operates at a slower rate than SRAM.
SRAM has a low packing density.	DRAM has a high density of packing.
It employs transistors and latches.	It makes use of capacitors and only a few transistors.
This form of RAM operates on the basis of switching the direction of the current.	This sort of RAM operates by storing charges.
SRAM is commonly found on processors or sandwiched between your computer's primary memory and processor.	The DRAM module is installed on the motherboard.
SRAM is a type of on-chip memory.	DRAM has off-chip memory properties.
Some typical applications of SRAM include L2 and L3 CPU cache units.	DRAM is commonly used as the primary memory in computers.
SRAM is a smaller memory chip.	DRAM comes with greater storage capacities.
SRAM has a storage capacity ranging from 1MB to 16MB.	DRAM has storage capacities ranging from 1 GB to 16GB.

You can also read about the Multilevel Queue Scheduling.

Frequently Asked Questions

Which RAM type is the fastest, and why?

SRAM (pronounced ES-RAM) consists of four to six transistors. In contrast to DRAM, which must be refreshed on a regular basis, it retains data in memory as long as power is available to the machine. As a result, while SRAM is quicker, it is also more costly, making DRAM the more common memory in computer systems.

Why is RDRAM named Rambus DRAM?

Rambus DRAM (RDRAM) is named after the firm that created it. It was popular in the early 2000s, mostly for video gaming devices and graphics cards, with transfer rates of up to 1 GHz.

Why is DRAM much preferred?

Data that is often accessed is cached for faster access. They both have their usefulness and may be found in current computers.  DRAM is inexpensive because it is significantly smaller than SRAM, allowing you to store more bits per space. It has a low power rating.

Conclusion

To summarize the article, we understood the major types of RAM, and how SRAM and DRAM work differently. We also discussed the key differences between both types. And lastly, we discussed some frequently asked questions based on types of RAM. But the knowledge never stops, so to better understand the operating systems, you can go through many articles on our platform.

Recommended Reading:

• Memory Hierarchy
• Introduction to Operating System
• Memory Hierarchy and its Characteristics
• Addressing Modes in Computer Architecture
• Functions of Operating Systems
• Types of Computer Memory
• Register in Computer

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