What’s the Difference between RAM and ROM?

Technology is a big topic on this blog.
Probably because inventors in this area are the genius to create new abbreviations each day. You can’t remember them as fast as they are published!
And even for older terms like these, not everyone really knows what they means

As a whole, RAM and ROM are two types of computer memories. The RAM is a buffer, where you can temporarily store some data to allow a program to work as quickly as possible. The ROM is a frozen memory, where we found the code of the program itself (it doesn’t exist anymore).

After this short introduction, we are now going to see in details how each one works, and also introduce what is replacing the ROM today



RAM is an abbreviation for “Random Access Memory”


Like often for technology, good definitions are hard to find in a dictionary
But this one probably helps the most:

RAM is the part of a computer in which information is stored while you are using it. RAM is an abbreviation for ‘Random Access Memory’.

Collins Dictionary

So it’s a data storage method (read and write), used for most computer devices (computers, smartphones, game consoles, etc.)

In computers the RAM is in the form of removable components that are easy to remove or replace (check here on Amazon what it looks like)


The RAM is used in most “smart” devices, such as computers, smartphones, etc.
It’s used to temporarily store certain information, useful for the execution of a program

Its use is quick, which allows storing and access data almost instantly (they measure this in nanoseconds)
In addition to being essential in a computer, it also improves the overall performance
For example if you have enough RAM, a video game will be able to store the level map to avoid loading times at each zone change

However, the storage space is usually quite limited
At the time I’m writing this, a standard computer has about 4 GB of RAM on average, you can install up to 100 GB on servers or specific configurations, but it will not go much higher
In comparison, a standard computer generally has at least 500 to 1000 GB of space on the hard disk, which is significantly higher (the goal is different, we will see later)

How it works

I’ll not go into the details of how RAM works on your computer because I don’t think that’s what you’re looking for
But I will try to illustrate this with an image

Imagine that you are a store owner
By opening your shop you make sure you have enough money in your cash register
At every sale you’ll store the money in the cash register because it is accessible quickly and easily
In the evening you will empty the cash register, and deposit the money in the bank

The cash register represents the RAM, or RAM. It is accessible easily and quickly, but its size is limited
The bank represents your hard drive. It takes longer to store your money, but its size is not a problem and your money is safe.

The RAM is empty when you start your computer, it fills up as you start programs, and when your computer turns off, everything is erased / lost



ROM is the abbreviation of “Read Only Memory”


It’s even hard to find a good definition for a ROM, as it doesn’t really exist anymore, but this one seems good:

A type of computer memory that holds information that can be used but not changed or added to

Cambridge Dictionary

Ok, to say this again differently, ROM is also a type of memory, but you can’t write data on it
So it’s written the first time, and then you can only read it
Also, data are not lost when shutting down the computer, unlike for the RAM


Originally the ROM contained a program, which can’t be modified by the user, for example:

  • The software in a phone (phones or old mobiles, not smartphone)
  • Video games sold in a cartridge (like Nintendo for example, check what it looks like on Amazon)
  • Some specific devices (the first GPS for example, or 3G dongles)

Now we also use the ROM word for firmware a manufacturer installs on a device
But they can be updated by an experimented user, for example:

  • Computers BIOS
  • Network hardware firmware (modem, router, switch, etc.)

To sum up, you can conclude that a ROM is generally a static memory, which you keep in the same state for a long time

How it works

The ROM operation is extremely simpler than for the RAM
Basically, it’s a CD-ROM that a manufacturer provides that you have to use like this with your device
This “CD-ROM” is attached in the device and can’t be modified

Other memory types

Hard drive

A hard drive is in the middle between RAM and ROM
It allows to store a large amount of data
(you can find 2 TB hard drives for a cheap price), but they have a limited speed

The growth of SSD hard drives, much faster, is revolutionizing this operation again, since now even with data stored on a hard drive we can minimize the slowdowns
And this is now at very interesting prices, there are SSD disks less than $30 (check my recommended drive here on Amazon)

SD Card

If we use hard drives on a computer or console, this is not the case for all devices
With the miniaturization of smartphones, cameras and cameras, SD cards still have a role to play
This is basically a removable hard drive, with reduced capacity

Today, however, there are SD cards can be up to 400 GB for a price relatively close to that of hard drives (check here on Amazon if you don’t know what it is)

USB key

Finally, the last storage I want to talk about are USB keys, you probably know them
The big advantage is that they are easier to use and simpler to carry than any other storage
It’s the perfect storage type to give a file to someone, whatever the hardware and software they have

We also find an important choices in stores, with storage capacity from 2 to 256 GB (check the prices here on Amazon)


To sum up, you have to remember that there are different types of storage type for computers and smart devices
Each one allow to store data and is chosen by the manufacturer depending on their needs

RAM stores data quickly but temporarily
ROM and other storage types are useful to store data for a longer time, but it’s slower

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