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Difference Between SSD and HDD

SSD and HDD are similar in their physical structure and specification; however, they follow different mechanisms to store the data. There are advantages and disadvantages of both these drives, and choosing the right one depends on the user's requirements and budget.

We are discussing significant differences between SSD and HDD in this article, which helps decide which one is superior to use in this modern era. Let's first understand both with the definitions:

HDD (Hard Disk Drive)

A hard disk drive is a non-volatile data storage device. The term non-volatile refers to storage that can store the data even when the power source is disconnected or turned off. An HDD contains mechanical platters and a moving head to read and write data. The head is usually attached with a small motor that helps spin the platters and move the header's arms.

Each platter is organized into several concentric circles, known as tracks. These tracks are further segregated into multiple logical units, known as sectors. Each track and sector number concludes a unique address that helps locate and access the data. The data is stored in the nearest available space. In most HDDs, the platters spin at a speed of 5400 RPM (revolutions per minute). The higher the number of RPM, the faster a hard drive will be to access data.


SSD (Solid State Drive)

SSD or Solid State Drive is a newer, faster non-volatile storage device. Unlike HDD, SSD does not include moving parts like platters, head, or arms. It uses integrated circuits to store and retrieve the data instantly. These ICs are coupled on an interconnected flash-memory chip (often dubbed as 'NAND') to achieve superior performance and durability. Without the moving components, SSD runs cooler and consumes less energy. This helps increase the battery life for laptops and other SSD-based devices.

The mechanism used in SSDs is similar to large USB drives; however, USB drives use a different kind of flash chips. That's the reason SSDs are expensive as compared to USB flash drives. The technology used in these storage devices is a NAND, a kind of flash memory. They include floating gate transistors that record a charge to store data at the lowest level. These gates are maintained in a grid style, which further turned into a block. Each row that helps organize gates as a grid pattern is known as a page. The data is stored in these organized blocks.


Key Differences between SSD and HDD

Few key differences between SSD and HDD are listed below:

  • The primary difference between SSD and HDD is that SSD is much faster in R/W speed. Even the cheapest SSD can achieve more speed than a traditional HDD.
  • Another big difference is the size. SSD can be as big as HDD, but it is also available in compact sizes similar to a RAM (Random Access Memory). Modern SSDs are assembled directly on the board.
  • One of the biggest key difference between SSD and HDD is the cost. SSDs are much costlier than HDDs. However, paying such an amount for SSD is still worthy due to its incredible performance and compact size.

Major Differences between SSD and HDD

The other significant differences between solid-state drives and hard disk drives can be explained in a tabulated form, as below:

Attribute SSD HDD
Complete Meaning SSD is an acronym used for Solid State Drive. HDD is an acronym used for Hard Disk Drive.
Mechanical Parts SSD does not include any mechanical parts. It only contains electronically designed components, such as integrated circuits (ICs). HDD is made up using mechanical parts. It includes platters, moving head and arms.
Physical Size SSD is available in different sizes. It can be either the same size as HDD or even smaller size as RAM. HDDs are comparatively larger. They are available in two sizes: 3.5 inches (for desktop systems) and 2.5 inches (for laptops and notebooks).
Weight Due to its compact size and no mechanical parts, SSD is light-weight compared to HDD. HDD is a bit heavier than SDD.
R/W Time The total number of R/W times is shorter in SSD. The total number of R/W times is higher in HDD.
Per second operations SSD can handle more I/O operations in a second. HDD supports fewer I/O operations in a second.
Latency SSD consists of higher latency. HDD consists of lower latency.
Fragmentation Issue SSD does not face fragmentation issues. HDD has fragmentation issues. It needs to be defragged from time to time as part of maintenance.
Data Transfer The data transfer is based on random access. The data transfer is sequential.
Cost SSD is much more costly than HDD. HDD is comparatively cheaper.
Release Time SSD is a newer storage solution, and it can be referred to as the future device. HDD is a much older storage option and termed as the traditional storage.
Noise There is no noise problem in SSD. HDD can produce noise while spinning or via other mechanical movements.
Reliability SSD is considerably more reliable. HDD contains mechanical parts, so there are chances of failures in these parts' functioning, making it less reliable than SSD.
Power Consumption Due to its non-mechanical nature, SSD consumes less power. This helps achieve better battery life. HDD consumes comparatively higher power to make its platters spin and move other parts along with it using a motor.

Which one should we choose?

As we said above, selecting the right storage is based on the user's requirements and budget. SSD can be best suited for those who cannot compromise with the performance, no matter how much they have to pay. Besides, HDD is the choice of those people who have basic tasks-processing requirements and want to get their system ready in the least possible budget.

However, the best possible way for balanced performance in a budget is to use both SSD and HDD. A computer system in today's technological era can work with both the storage simultaneously. Therefore, a low-capacity SSD having OS installed in it will work better with a traditional HDD. SSD can only be used for the software, whereas the user's data (like images, audio, video, documents, etc.) can be stored in an HDD. This will help system software and activities run faster and provide optimum performance.

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