Types of RAM and ROM | Definition- 8 Types Of DRAM| Detailed

Types of RAM and ROM

Different Types of RAM and ROM and what makes the difference in both memory types. Firstly you are going to read about what is Ram and Rom?

Random-access memory and Read-only memory are both is a memory used in the computer system known as computer memory.

It only stores real-time data and programs because the RAM is a volatile memory that erased all data when you switch off the computer.

But Rom memory is non-volatile and it doesn’t erase your data even your computer is switched off.

In simple words, you can say both memories are the type of computer memory but they are different from each other based on their usage, the capacity of memory, speed, and storage feature.

Before going to know about types of RAM  and ROM, firstly you should read about basic things about them, for example, what is Random access memory?

What is (Random Access Memory) RAM?

Random-access memory is a computer memory that can be accessed randomly; i.e. any byte of memory can be retrieved without affecting the preceding bytes.

Random-access memory is the common type of memory found in computer devices, for example, printers. Ram refers to Read and writes memory; means you can write data in RAM and also read data.

Types of RAM and ROM

You already know that RAM is a volatile memory, which means that it requires a steady flow of electricity to maintain its contents. when the power is turned off, everything is in RAM is lost.

It can store everything that is running on the computer system, anything means browser (cached) data, whether you are using text editor or image or video editing tools.

Some Related Topics-

Types of RAM and ROM 

In this topic of Types of RAM and ROM, There are Mainly Three types that are used by us. Also, we are adding Subtypes.

Types of RAM and ROM – DRAM, SRAM, and MRAM are the types of RAM, and PROM, EPROM, and EEPROM are the types of ROM

Types of Random Access Memory (RAM)

Dynamic RAM (DRAM): DRAm is a type of physical memory used in most personal computers. The term dynamic shows that the memory must be continuously refreshed or it will lose its contents.

Static RAM (SRAM): Static random access memory is a type of memory that is faster and more reliable than the more common DRAM. Their name is static because they don’t need to refresh like DRAM.

Magnetoresistive RAM (MRAM): This a newer type of memory that stores data using magnetic charges instead of electrical charges. manufacturers say that MRAM has a larger storage capacity, fewer power consumables, and faster access times than other RAM. MRAM retains its contents after power is removed from the computer, Which saves our data after power loss means this is a type of Non-volatile RAM memory.

Types of Dynamic RAM (DRAM)

Types of RAM and ROM, In this there are some subtypes of DRAM take place and you are going to read about them.

DRAM is available in several different technology types. All of these different memory types are the same as others.

when processors get fast, memory also needs to run fast and more efficiently. memory companies have invented progressively faster memory architectures to allow memory speed to increase. There are 8 different types of DRAM are:

Conventional DRAM: This is the oldest and slowest DRAM technology. It uses the standard memory addressing method, where the first row and column be sent to the memory, and then the column address. But now this is not used on any new system and having replaced by others.

Fast Page Mode (FPM) DRAM: This is slightly faster than conventional DRAM. while DRAM needs that a row and column be sent for each access, FPM worked by sending the row address just once for many access to memory in a location near each other, improving access time. FPM is the slowest memory used in modern Personal computers.

Extended Data Out (EDO) DRAM: EDO also called hyper page mode DRAM. This is faster than FPM memory because of another transformative tweak in how the memory access work. EDO has had its timing circuits changed (modified) so one access to the memory can begin before the last one has completed. It gives a performance boost of around 3-5% over FPM in most systems.

Burst Extended data out (BEDO) DRAM: This is also an evolutionary improvement in conventional asynchronous RAM. EDO memory is merged with pipelining technology and special latches to allow for a much faster response time than regular extended data out EDO. BEDO memory allows the use of a much higher memory bus speed than EDO.

Synchronous DRAM (SDRAM): this is different from earlier types in that it does not run asynchronously to the system clock the way older, conventional types of memory do. SDRAM is tied to the system clock and designed to be able to read or write from memory in burst mode at 1 clock cycle per access at memory bus accelerate up to 100 MHz or higher. SDRAM accomplishes its faster access using a number of internal work improvements, including internal interleaving, which authorizes half of the module to start while the other half is finishing one.

Double data rate SDRAM (DDR SDRAM): this is similar to SDRAM, but doubles the bandwidth of the memory by transferring data twice per cycle on both the rising and falling edges of the clock signal. The clock signal transitions from “0” to “1”  (rising edge) and then again back to “0” (falling edge) each cycle.

Direct Rambus DRAM (DRDRAM): DRDRAM works like an internal bus than a conventional memory subsystem. it is based around a direct Rambus channel, a highspeed 16-bit bus running at a clock rate of 400 MHz. As with DDR SDRAM, the transfer is accomplished on the rising and falling edges of the clock, yielding an effective theoretical bandwidth of approximately 1.6 GB/Second. This is a different approach, the way memory is currently worked over a wide 64-bit memory bus. DRDRAM is proprietary and is being designed to use a special type of module called Rambus inline memory module, Or RIMM.

Synchronous-Link DRAM (SLDRAM): SLDRAM improves the performance of the memory sub-system over SDRAM, The specification for SLDRAM call for a 64-bit bus running at 200 MHz clock speed. As with DDR SDRAM, a transfer is made twice on each clock cycle, for an effective speed of 400MHz. This yields a net theoretical bandwidth of about 3.2GB/second, double that of DRDRAM. Finally, SLDRAM is an open standard, meaning that no royalties need to be paid any more in order to make use of it.

Static RAM (SRAM)

Static RAM holds its data without any external refresh for a long time as power is supplied to the circuit. This goes against dynamic RAM (DRAM), the memory refreshed many times per second in order to hold and store its data contents. SRAMs have the following strength over DRAMs.

  • Simplicity: SRAMs don’t need an external refresh circuitry in order for them to keep their data intact
  • Speed: SRAM s faster than DRAM.

There are some following weaknesses of SRAMs over DRAMs.

  • Cost: SRAM is a byte for byte, several times more expensive than DRAM.
  • Size: SRAMs take more space than DRAMs.

In this topic, Types of RAM and ROM we have completed the types of RAM section and now below you can also read about ROM and Types of Read-only Memory.

 What is Read-Only Memory (ROM)?

A computer memory on which data has been prerecorded Is called ROM. when the data has been written on a ROM Read-only memory chip, it cannot be erased or removed it can only be read.

Types of RAM and ROM

Unlike the main memory, ROM retains its contents even when the computer is turned off. ROM is non-volatile, and the RAM is a type of volatile memory.

Types of ROM 

In this topic of Types of RAM and ROM, there are three types of Read-only Memory.

Programmable Read-only memory (PROM):  PROM is able to re-programmed by using Prom Programmer. Generally, a PROM can be changed or updated only once.

Erasable programmable ROM (EPROM): This type of ROM can have its contents erased by ultraviolet light and then reprogrammed by a PROM programmer. This procedure can be carried out many times but the constant erasing and rewriting will eventually render the clip useless.

Electrically EPROM (EEPROM): This type of ROM works similar way to flash memory in which its contents can be flashed for erasure and then written to without having to remove the clip from its environment. EEPROMs are used to store the computer system BIOS and can be updated. *Flash memory – this is an uncommon type of EEPROM that can be erased and also reprogrammed in blocks rather than one byte at a time.

Related Topic: Primary Storage devices V/s Secondary Storage


RAM is called the primary memory or main memory that stores data and instruction temporarily in the computer opposite as ROM refers to memory chips storing permanent data and instruction.

Now, this becomes clear that both memories have their own features, the first one is used to taking instruction while operating things, and the second one is used to store permanent data.

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Frequently Asked Questions (FAQ)

What are RAM and ROM?

Random-access memory and Read-only memory are both is a memory used in the computer system known as computer memory. It only stores real-time data and programs because the RAM is a volatile memory that erased all data when you switch off the computer. But Ram memory is non-volatile and they don’t erase your data even your computer is switched off.

Types of RAM?

Dynamic RAM (DRAM)
Static RAM (SRAM)
Magnetoresistive RAM (MRAM)

Types of ROM?

Programmable Read-Only Memory (PROM)
Erasable programmable ROM (EPROM)
Electrically EPROM (EEPROM)

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