Mobile Phone RAM, ROM Definition, Type and Difference

Mobile phones, like computers, have both RAM (Random Access Memory) and ROM (Read-Only Memory). Both are crucial components, and they serve different purposes.

This post will examine RAM and ROM definitions, types, and differences.

Mobile Phone RAM and ROM Definition

RAM (Random Access Memory)

Function: RAM is the memory that temporarily stores the data that your device is currently using or processing. Think of it like the short-term memory of your device. When you run an app, for instance, it's loaded into RAM because accessing data from RAM is much faster than from an internal or external storage device.

Volatility: RAM is volatile, meaning it loses its data when the device is turned off. So, anything stored in RAM is cleared out when you reboot your device.

Size: As of my last training data in 2021, mobile phones typically come with 2GB to 16GB of RAM, with high-end models boasting up to 18GB or more.

Importance: More RAM typically means better multitasking capabilities. For instance, if you switch between apps frequently, having more RAM helps retain those apps in memory, allowing for quicker switching without reloading the app entirely.

Random Access Memory

ROM (Read-Only Memory)

Function: In the context of mobile devices, when people refer to ROM, they usually mean the internal storage or memory where the phone's operating system, applications, and other files are stored. Technically, this memory isn't strictly "read-only" since we can write to it (when we install apps, save photos, etc.), but the term ROM has traditionally been used in this context.

Types: There are different types of ROMs, like firmware, which is embedded in a chip and cannot be easily modified by end-users. Custom ROMs are also popular in the Android community; these are modified versions of the Android OS that can be installed to replace the stock operating system of a device.

Size: As of 2021, typical ROM sizes in mobile phones range from 16GB to 512GB, with some luxury or specialized phones offering 1TB or more.

Importance: More storage means you can have more apps, more photos, more music, and other files stored on your device. Running out of storage can cause performance issues or limit the device's functionality.

Read-Only Memory

RAM and ROM Type

RAM Type

1. DRAM (Dynamic Random Access Memory):

Function: It's a type of RAM that stores each bit of data in a separate capacitor. It needs to be refreshed thousands of times per second.

Usage: It is the most common type of RAM found in computers and other devices, including mobile phones.

Dynamic Random Access Memory

2. SRAM (Static Random Access Memory):

Function: Unlike DRAM, SRAM doesn't need to be periodically refreshed, as it maintains its data bits as long as power is applied. This makes it faster than DRAM.

Usage: Due to its speed, it's used for cache memory in CPUs.

Static Random Access Memory

3. LPDDR (Low Power Double Data Rate):

Function: A type of DRAM designed for mobile devices with lower power consumption.

Variants: Over time, it has evolved with LPDDR2, LPDDR3, LPDDR4, and LPDDR5, with each newer generation generally offering improvements in speed, efficiency, and architecture.

Low Power Double Data Rate

ROM Types:

1. PROM (Programmable Read-Only Memory):

Function: A type of ROM that can be programmed only once. After data has been written onto it, it cannot be modified.

Programmable Read-Only Memory

2. EPROM (Erasable Programmable Read-Only Memory):

Function: Unlike PROM, the data stored in EPROM can be erased and reprogrammed. Erasing is typically done by exposing the EPROM chip to UV light.

Erasable Programmable Read-Only Memory

3. EEPROM (Electrically Erasable Programmable Read-Only Memory):

Function: Similar to EPROM, but it can be erased electrically rather than using UV light. It can be erased and reprogrammed multiple times without removing the chip from the device.

Electrically Erasable Programmable Read-Only Memory

4. Flash Memory:

Function: A type of EEPROM that can be erased and reprogrammed in blocks instead of one byte at a time. It's non-volatile, meaning it retains its content even after power is turned off.

Usage: This is the most common type of ROM used in mobile devices, USB drives, SSDs, and other storage devices because of its versatility.

Flash Memory

Difference between RAM and ROM

Both RAM and ROM are essential components of computers and many other electronic devices, but they serve different purposes and have distinct characteristics. Here's a breakdown of their differences:

1. Purpose:

RAM: Provides short-term memory storage for processes running on a computer or device. It's used for temporary storage of data that the CPU might need to access quickly.

ROM: Provides long-term storage and typically contains firmware or software that boots up the computer or device. It's used for permanent storage of data that doesn't change often.

2. Volatility:

RAM: Volatile. This means the data stored in RAM is lost when the device is turned off.

ROM: Non-volatile. The data in the ROM remains even after the device is turned off.

3. Write Ability:

RAM: Read and Write. Data can be both read from and written to RAM.

ROM: Read Only (in its traditional sense). Data is generally written to ROM during manufacturing and cannot be modified by the end user. However, certain types of ROM, like EEPROM or Flash memory, can be written multiple times.

4. Usage:

RAM: Used for general system operations, running applications, and multitasking.

ROM: Used to store firmware or software that's used to boot up the device. In mobile phones, it's also commonly used to refer to internal storage, although technically, internal storage uses Flash memory, which is writable.

5. Size and Speed:

RAM: Typically has a larger capacity than ROM in a computing device. It's also faster in terms of data access.

ROM: Usually smaller in size when compared to RAM. Slower than RAM.

6. Physical Form:

RAM: Often comes in the form of sticks or modules, especially in desktop computers.

ROM: Often integrated onto the motherboard or in the form of chips on a device.

7. Examples:

RAM: DRAM, SRAM, LPDDR (in smartphones).

ROM: PROM, EPROM, EEPROM, Flash memory.

Advantages and Disadvantages

RAM (Random Access Memory)


1. Speed: RAM offers fast read and write speeds, allowing CPUs to access data rapidly. This speeds up processing times and system operations.

2. Volatility: While this might seem counterintuitive, the volatile nature of RAM can be seen as an advantage in some scenarios. Sensitive information is not permanently stored and is wiped off when the power is off, which can be a security benefit.

3. Multitasking: Adequate RAM allows for smooth multitasking on devices, allowing users to switch between applications without lag or delay.

4. Direct Access: Data can be directly accessed in RAM, irrespective of its location, ensuring efficient data retrieval.


1. Volatility: Data loss occurs if there's a power interruption. Unsaved data can be lost as the RAM doesn't retain its content without power.

2. Cost: RAM, especially the latest and fastest versions, can be more expensive per byte compared to storage memory.

3. Physical Size: To increase RAM, particularly in devices like PCs, you need to physically add more RAM modules, which may be a limitation for some devices.

4. Degradation: Over time, especially with constant intensive usage, RAM can degrade, affecting performance.

ROM (Read-Only Memory)


1. Non-Volatility: ROM retains its data even when the power is turned off, which is especially crucial for firmware and boot-up software.

2. Durability: Generally, ROM has a longer life than RAM. Since data isn't continuously written and erased, wear and tear are lesser.

3. Consistency: ROM provides a consistent software environment as its data is not usually changed.

4. Security: Given its read-only nature (in traditional ROMs), it's harder for malicious software to alter its contents.


1. Limited Write Cycles: Some types of ROM (like Flash memory) have a limited number of write and erase cycles before they wear out.

2. Read-Only: Traditional ROM can't be easily modified or updated, which could be a limitation if firmware needs an update.

3. Speed: While ROM can be fast, it's generally not as fast as RAM in terms of data access.

4. Cost: High-capacity ROM storage (like SSDs based on Flash memory) can be expensive, especially when compared to traditional hard drives.

When selecting a device, it's crucial to consider both its RAM (Random Access Memory) and ROM (Read-Only Memory) capacities, as these can significantly influence the device's performance and storage capabilities. For those who mainly engage in casual activities such as web browsing, checking emails, or using basic applications, a device equipped with 2GB to 4GB of RAM paired with 32GB to 64GB of ROM should suffice.

This configuration ensures smooth operations without unnecessary expenditures on high-end specifications. However, if your usage leans more towards moderate to intensive tasks, like gaming, heavy multitasking, or frequent media consumption, it would be advisable to opt for a device with 4GB to 8GB of RAM. Furthermore, a ROM capacity of 64GB to 128GB would be more suitable for storing larger apps, games, and multimedia files. Always align your device choice with your primary activities to ensure a seamless and lag-free user experience.