Difference between Hard Drive and Memory

Hard Drive and Memory are both used for the same purpose of storing data. For long-term data retention, we need to use the Hard Drive storage device. On the other hand, the memory storage device is used for short-term data retention.

Hard Drive or HDD is slower than the memory but it stores more data. Memory or RAM (Random Access Memory) is faster as compared to the Hard Drive but data will be lost when the power supply is switched off.

Read this article to find out more about Hard Drive and Memory and how they are different from each other.

What is Hard Drive?

Hard Drive is a collection of magnetic disks, used to store the digital information on a computer. HDD consists of read/write head which read and writes the data to the disc, and it also consists of spinning disks or platters which are coated with the magnetic material. To access the certain sectors on the disk surface where the data is stored as a magnetic pattern, then the head moves quickly across the surface.

Hard Drives can store huge amounts of data, which is measured in gigabytes or terabytes. These are the most important component of the modern computers. Through USB it is connected to the computers. Failure of mechanical, electrical, or file system corruption may lead to the data lost in the Hard Drives. To overcome the failure or file system corruption of the data lost, we need to take the back up regularly.

In general, there are two types of Hard Drives −

  • Mechanical Hard Drives − To store data Mechanical Hard Drives uses the spinning disks. Due to the low cost and large storage capacity it is used widely and it has been using from decades. It is also known as the HDD.

  • Solid Sate Drives − Solid State Drives use the flash memory to store the data and it has no moving parts. These are faster, durable and expensive also comparing to the mechanical hard drives. It is also known as SDD.

What is Memory?

Memory is made of registers. It refers to a location of data in which each register in memory is one storage location. Memory is used when data is to be stored for a short time span. It can be identified by using Address. It is smaller than the Hard Drive.

They are three types of Memory −

  • Primary Memory − Primary Memory is used to store the data for the short-term time. The data can be retrieved fast comparing to the secondary memory. The data which is in the primary memory can be lost when power is lost and computer is turned off. To avoid the loss of data in primary memory the data must be stored in a secondary memory.

  • Secondary Memory − Secondary memory are also called as a auxiliary or external memory, where the data will be stored for the long term. And the data cannot be lost even when the power is off or computer is turned off. The HDD (Hard Disk Drives), SDD (Solid State Drives), and USB drives are some of the examples of secondary memory. Some of the advantages of the secondary memory are Large Storage Capacity, Cost-Effective, and Durability.

  • Cache Memory − Cache memory is small in size when comparing to the main memory. The data which is stored in the cache memory is copied temporarily from the main memory. Cache memory contains the three levels and they are L1, L2, and L3. The Level 1 i.e., L1 is the smallest and fastest.

Differences between Hard Drive and Memory

The following table highlights the major differences between Hard Drive and Memory −


Hard Drive



Magnetic Disk made of aluminium and used main storage device

Electronic component capable store data


Capacity is low

Capacity is high


It has high run speed

It has low run speed

Power Supply

Doesn’t require power supply to retain data

Requires power to hold data


It has platters and disks

It has chips


Less Cost

More Cost

Storage Capacity

Hard Drive capacity ranges between 128 MB to 1 MB

Memory capacity ranges between 1 GB to 1 TB


It is Portable

It is not Portable


Large volumes of data can be stored on hard drives for a longer period, but they have slow access times as compared to the memory. Memory is used for short term data storing and processing. Memory has a faster access time but a limited storage capacity. It is important to understand the difference between the two storage devices in order to manage the data storage and boost the performance of the computer.

Updated on: 02-Mar-2023


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