What Is the Difference Between Random Access Memory (RAM) and Read Only Memory (ROM)?

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What Is the Difference Between Random Access Memory (RAM) and Read Only Memory (ROM)?

When dealing with computers and similar electronics, buyers may run across the termsRAM and ROM. It is important to know the difference between these two types of memory when selecting computers and other items. When evaluating the differences between these different types of memory, buyers should look at different aspects, including speed, type of storage, and other features. It is also important to realise that RAM and ROM have different subtypes. For example, buyers can select from DRAM and SRAM as well as PROM and EPROM. These different types offer various features, so it is important for a buyer to know what he or she needs.

In addition to learning about ROM and RAM in order to buy electronics, buyers may also want to know how to expand memory. Whether a buyer is looking to purchase a computer or just more memory for his or her computer, it is possible to find these products in traditional computer stores and online at retail sites like eBay.

Differences Between RAM and ROM

RAM (random access memory) and ROM (read only memory) are two different types of memory that are used in computers. A buyer should learn about the differences between the RAM and ROM in computers and other devices. RAM is volatile memory, which means that the data can be deleted. ROM is the non-volatile part of the memory where the permanent data that is necessary for operating the computer system is written. Another difference is that RAM needs electricity in order to work, so the information stored in RAM is lost whenever the computer is turned off. ROM does not need electricity in order to preserve the data, so it retains the information when the computer is turned off.


RAM and ROM have different speeds. The computer finds it much faster to access RAM, and increased RAM helps the processor speed up, as well. ROM tends to be slower, and it cannot boost a computer's processing speed.

Type of Storage

Buyers should also realise that RAM is only used for storing temporary information, so it makes sense that the computer can access it faster than it can access ROM. ROM is used for storing permanent information, which generally means slower access and processing.

Other Features

Both the speed and type of storage are important, but the buyer should also take some time to consider additional aspects of the two types of memory, including structure, memory function, cost, and chip size. RAM chips tend to be a lot larger than ROM. The structure of the two chips is also different, as RAM is a rectangular-shaped chip that is inserted into the computer's motherboard, and ROM tends to be an optical drive that is made of magnetic tape. The memory functions differ, which means that with RAM, both read and write operations can be performed. With ROM, on the other hand, only read operations can be performed since the user cannot make changes to the chip.

Types of RAM

A buyer should learn about the different types of RAM before attempting to buy RAM modules. Different types of RAM have different capabilities. It is important that a user knows which RAM suits his or her purposes. Some of the various types of RAM available on the market include SRAM and DRAM, each of which has a number of subtypes.


SRAM , or static random access memory, has multiple transistors, usually between four and six. This kind of memory chip is usually used as cache. It does not have a transistor in each cell. Although SRAM is the faster option, it also tends to be more expensive than DRAM.


DRAM , or dynamic random access memory, has memory cells with a capacitor and paired transistor. This kind of memory requires constant refreshing. A buyer can also choose from a number of different subtypes of DRAM, includingEDO DRAM and SDRAM.

Types of ROM

Buyers can find five different basic types of ROM on the market, including ROM, PROM, EPROM, EEPROM, and flash memory. All of these types of ROM are non-volatile and unchangeable, but they still have some differences among the various types of ROM. Thus, a user should at least have a basic understanding of them.


ROM is the standard for this type of memory. Because of the way ROM is designed, it is essential that the chip needs to be programmed perfectly with the correct data in order for it to work accurately. These kinds of chips cannot be rewritten or reprogrammed. Thus, if it is incorrect or the data needs to be updated in some way, there is no way to salvage the chip. Once they are completed, however, ROM chips tend to be very inexpensive.


PROM , or programmable read only memory, is more fragile than ROM, and it can only be programmed once. Because of this limitation, PROM tends to be inexpensive.


EPROM , or erasable programmable read only memory, tries to do away with the problem of PROMs only being able to be used a single time. This type of memory can be rewritten many times. In order to be erased, however, the user has to use a special tool for the task.


EEPROM , or electrically erasable programmable read only memory, is another step up from EPROM because EEPROM chips do away with some of the drawbacks. For example, EEPROM chips do not need to be removed to be rewritten. Additionally, a portion of the chip can be changed without erasing the entire chip. Furthermore, it does not require special equipment to rewrite the chip.

Flash Memory

Flash memory is another type of ROM that is actually a type of EEPROM chip that attempts to further improve on the technology. Flash memory tends to be faster than normal EEPROM chips because it tends to write data in chunks instead of one byte at a time.

Expanding Memory

Buyers should know that they can purchase more RAM rather easily for computers and other electronic devices whenever they need more memory. When first purchasing a computer, it is a good idea for the buyer to think about how much RAM he or she needs. This depends on what he or she tends to do with the computer. RAM comes in microchips of different sizes, such as 256 MB, 512 MB , 1 GB, 2 GB, or more. If a buyer engages in activities that require a lot of memory, such as gaming, 3D modelling, or similar activities, then he or she needs more RAM than someone who is simply checking his or her email or shopping on the Internet.

On the other hand, ROM is permanent and is typically built into the device, so it is difficult to purchase it separately. Generally speaking, the buyer is limited to whatever ROM was included when he or she purchased a computer.

Finding RAM and ROM on eBay

It is also possible to find RAM and ROM on eBay, especially if you know how to best take advantage of the site's search tools. Although a variety of tools are available, it may be easiest to run a keyword search first. You should type keywords, such as RAM, into the search box. If you do not want to look through all the product listings, you can narrow it down by selecting certain filters.

You should also keep in mind some of the other useful tools that eBay offers. For instance, if you want to learn more about a computer's specs or purchasing RAM, you can make use of the tool that allows you to contact a seller. This tool can be found on the product listing's page. Another tool you should check out is the feedback tool. With this, you can see what other buyers have said about a particular seller to help you decide whether or not to make a purchase. After you have made a purchase, you can also leave feedback to help other buyers make purchasing decisions.


Those who are new to electronics may be unsure of the difference between RAM and ROM, which are different types of memory found in computers and some other electronic devices. Computers need both types of memory, as they perform different functions in the computer. ROM is used for storing permanent information and running the operating system of a computer. RAM, on the other hand, is used for temporary information that disappears when the computer is turned off. A buyer should understand the various differences between the two types of memory in order to purchase the right type for his or her needs.

Furthermore, a buyer should understand that he or she can select from different kinds of ROM and RAM. Some of the various types on the market include SRAM, DRAM, ROM, PROM and EEPROM. A buyer can purchase more RAM, but the amount of ROM in a computer is generally set when the computer is built. A buyer should always consider what he or she needs to do with a computer, and if more memory is needed in the future, buying additional RAM modules is a possible option.

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