[TOPIC]What is the difference between HDDs and SSDs?

Learn types of storages for choosing a PC

“Data storage” is essential for PC. All PCs have an area called internal storage to store data, and all are stored in the internal storage, such as programs related to the basics of a PC like OS and software running on a PC. Therefore, sometime the operation of the PC depends on the performance of the internal storage.

Previously, “HDD” is mainly used for internal storage, while recently the number of PC using “SSD” is increasing. It is important to understand the difference between HDDs and SSDs to select a suitable PC.

This content introduces the basic difference between HDDs and SSDs.

  1. Index
    1. What is an HDD?
    1-1. Advantages
    1-2. Disadvantages
  2. 2. What is SSDs?
    2-1. Advantages
    2-2. Disadvantages
  3. 3. HDDs gradually break down due to a mechanical drive
  4. 4. Do SSDs have a lifetime?

・1. What is an HDD?

HDD is an abbreviation for hard disk drive. It is a storage device which electromagnetically writes and reads data and programs.
In HDDs, there are multiple disks coated with magnetic material called a platter which records data. A magnetic head writes and reads data on platters.

・1-1. Advantages

Larger amount of data can be stored in one drive than SSD
Low cost per capacity

・1-2. Disadvantages

Structurally vulnerable to impacts
Higher power consumption

・2. What is SSDs?

SSD is an abbreviation for solid-state drive, which means a storage drive using a semiconductor memory. It is a kind of storage drive same as HDD. HDDs have been used for many years as a medium for storing large amount of data. However, with the increasing capacity of SSDs in recent years, SSDs are rapidly becoming popular.

2-1. Advantages

Strong against impacts
Less heat generation
Lower power consumption
Very fast reading and writing
No operating noise
Smaller and lighter than HDDs
Various shapes contribute to downsizing of PCs

・2-2. Disadvantages

Low capacity
High cost per capacity
Difficult to retrieve data due to a sudden breakdown

・3. HDDs gradually break down due to a mechanical drive

To shock a HDD while it is working should be carefully avoided. When the magnetic head is shocked, it falls off from the platter, and at the next moment, the magnetic head is struck into the platter due to a reaction to the shock. Then the magnetic coating on the platter is scratched and peeled off from the platter. The area becomes a “bad sector”.

It is scary that an HDD can operate even there is a “bad sector”. If you continue to operate the hard disk, it may cause more serious damage on the head part. Every time a physically damaged part is accessed, the head is also damaged. As a result, it falls into the worst situation, such as a PC is unable to recognize an HDD, or an HDD continuously generates abnormal noise.

Therefore, it is recommended that regularly inspect an HDD and save data to a new storage as soon as possible when bad sectors increase.

・4. Do SSDs have a lifetime?

SSDs actually have a lifetime. The minimum unit for recording data in flash memories used for SSDs is called a cell, and this cell gradually deteriorates. In the case of general NADN flash memory, the lifetime ends when the cell writes and erases about 1,000 to 10,000 times. If you need to rewrite a large amount of data everyday frequently, it is better to choose an HDD.


HDDs and SSDs have the same purpose of storing data, however there are differences in structure and features. When purchasing a new PC, it is a good idea to check what your purpose is and which type of internal storage the PC has.

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