Difference Between SSD and HDD

Edited by Diffzy | Updated on: May 14, 2023


Difference Between SSD and HDD

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When browsing for laptops, you can see that some of them are labelled SSD, while others are labelled HDD. SSD (Solid State Drive) and HDD (Hard Disk Drive) are storage devices. They provide extra storage and help to speed up the workings of the device. SSDs and HDDs vary drastically. This article provides insight into the difference between the two, so you can make an informed decision when choosing between the two.


Solid State Drive uses microchips for storing and accessing data. It provides non-volatile data storage. SSDs do not have any moving parts within them, so they do not generate noise and heat. The performance power of SSDs is not affected by fragmentation. A few advantages SSD disk has over HDDs are that, they are faster, durable, shock resistant, and lighter. A few disadvantages are, that SSDs have a shorter lifespan, less storage and are costlier. Laptops with SSDs can be chosen for storing operating systems, frequently used files, and gaming apps.

Hard Disk Drive uses spinning platters for storage and read/write functions. SSD disk contains moving parts within them, which makes the disk vulnerable to damage. Plus, the moving parts generate noise and heat when operating. The performance of HDDs is affected by fragmentation. The disk needs to be defragmented periodically. A few advantages HDDs have over SSDs are that, they have a longer lifespan and are less expensive. HDDs should be chosen if you want to add extra storage for storing personal files.

Difference between SSD and HDD in Tabular Form

Parameters of Comparison



Full form

Solid State Drive

Hard Disk Drive


Faster than HDD

Slower than SSD

Heat and Noise

Do not generate heat and noise

Generates heat and noise


SSD uses less power

HDD uses more power


The performance of SSD is not affected by fragmentation

The performance of HDD worsens due to fragmentation. The need to be defragmented.


Does not contain any moving parts

Contains moving parts


An SSD is lighter than HDD

HDD is heavier than SSD.

Vibration Effects

Can withstand vibrations

Vibration can affect the moving parts in HDD



Cheaper than SSD


Less than HDD.

More than SSD.

Data Transfer

Not sequential.



More durable. It is shock-resistant.

Less durable. It is fragile.


Best used for storing operating systems, frequently used files and gaming apps.

Best used for storing extra data. For example, documents, movies, and photos.


Shorter lifespan compared to HDD

Longer lifespan compared to SSD.

What is SSD?

SSD is the acronym for “Solid State Drive.” SSDs use flash memory to store data inside an integrated circuit. The use of flash memory in SSDs means that the information is written, transferred and erased silently and electronically. It helps to speed up the performance of a computer. SSDs provide non-volatile data storage; that is the data once stored won’t disappear when the device is turned off. Compared to HDDs, SSDs don’t have moving parts. In the past SSDs had lesser storage capacity than HDDs, but they have since improved. Nowadays, you can find SSDs with large storage capacities. SSDs have better speed; they are compact, more durable, and consume less energy.

Characteristics of SSD

Speed of SSD

SSD is said to be eight times faster than an HDD.

Sound effects in SSD

SSDs do not consist of any mechanical moving parts within them. They are made with integrated circuits. Hence, SSDs do not make any noise when operating.

Data transfer in SSD

Unlike in HDD, data transfers in SSD are not sequential. It follows random access. This feature helps to speed up the process of data transfer. Since the physical location of the data needed is not important, there is consistent read performance in SSD. SSD experiences no delays due to head motion because they have no read/write heads.

Reliability of SSD

The reliability of SSDs is higher compared to HDDs. Unlike HDDs, SDDs do not consist of moving parts, which eliminates the risk of mechanical failure.

SSDs are not affected by magnetic forces.

Storage capacity of SSD

SSDs use memory chips to store and access data. SSDs have lower storage capacity than HDDs. Since SSD has a higher cost, it was sold with smaller storage sizes. Laptops using SSD had only 128 GB and 256 GB storage.

The introduction of 3D NAND helped resolve the storage issue. In simple terms, 3D NAND is the process where memory/silicon chips are stacked on top of each other. This helps to increase the speed of your devices, help them to hold more information, use less energy for working, and run more efficiently. SSDs with 3D NAND have more storage capacity. Currently, SSD is available with storage capacities ranging from 120 GB to 30 TB.

Defragmentation in SSD

Unlike HDDs, SSDs do not have any physical restrictions for the read/write head. Therefore, no matter where the required data is stored within the disk, it does not affect the disk’s performance. Fragmentation does not affect SSDs; therefore, they do not need to be defragmented.

Components and operation of SSD

SSD drives do not contain any moving parts. They use microchips for operating. An SSD drive consists of the following components,

  • Controller: This is embedded in the processor responsible for executing firmware-level software. This is an important factor which affects SSD performance.
  • Cache: This is where the directory of block placement is stored. In addition, the wear levelling data are also stored here.
  • Energy storage: This consists of batteries or a capacitor. This is useful if the power in the drive gets dropped. In this situation, the data stored in the cache is moved to the drive.
  • DRAM volatile memory: The old primary storage component.
  • NAND flash memory: The current primary storage component. As the number of parallel NAND flash chips used in the disk increases, the performance of the SSD increases.

Different types of SSD

  • PCIe and NVMe SSDs: the PCIe (peripheral component interconnect express) is typically used to connect network cards, graphic cards, or other high-performance hardware. It provides users with low latency and high bandwidth, thereby proving super-fast communication between the CPU and SSD. PCIe-using SSD drives are based on NVMe (Non-volatile Memory Express standard). The NVMe has 32 GB per second of raw throughput. It runs at a speed of up to 7 GB per second.
  • Traditional SSDs, mSATA III, and SATA III: SATA (Serial Advanced Technology Attachment) is an old version of the SSD interface. It was developed specifically for storage purposes. It has a speed of about 6 GB per second. This interface is not used nowadays, as users prefer the much faster NVMe.

Benefits of SSD

  1. Business: SSDs are the superior option for use in companies working with huge amounts of data, such as data analysis companies, programming, financial firms, etc. SSDs provide them with faster access times and file transfer.
  2. Gaming: Modern games are constantly loading and writing files like textures, levels, maps, characters, etc. Therefore, they need laptops with better storage facilities. All new gaming consoles (PS5 and Xbox Series X) use SSDs.
  3. Mobility: SSDs require less power for operating than HDDs. Therefore they contribute to better battery life in tablets and laptops. Further SSD drives are shock resistant. This feature helps reduce the chances of data loss if the devices are dropped.
  4. Servers: enterprise serves opt for SSD drives because their fast read and write time help them to serve clients better.

What is HDD?

HDD is the acronym for “Hard Disk Drive.” It is a traditional storage device. HDD uses spinning platters to read and write data. Compared to SSDs, HDDs have increased storage capacity. They also provide easy data recovery if the drive is damaged.

Characteristics of HDD

Speed of HDD

For the reading and writing operations, HDD disks use spinning platters of magnetic drives. The spinning platters slow down the start-up speed of the HDD. HDD is slower than SSD.

Sound effects of HDD

HDD drives have mechanical moving parts within them. The movements of these parts are required for HDDs to function. Because of these moving parts, HDD drives are noisy. HDD drives having smaller sizes, 2.5 inches are comparatively quieter.

Data transfer in HDD

The data transfer in HDD occurs sequentially. To elaborate, the physical read/write head of HDD seeks the correct point in the hard drive to perform the needed operation. The time needed to seek this information is significant; therefore speed in HDD is lower. The data transfer in HDD is also affected by the layout of the files and the file system fragmentation. Since hard disk drives have a mechanical nature, it leads to performance limitations.

Reliability of HDD

HDD has many moving parts inside it. The inclusion of these moving parts in the HDD makes it more vulnerable to damage. For an HDD to function, the platters and heads inside the disk move in a rapid motion. This rapid motion of the parts can make HDD vulnerable to “head crash.” There are several reasons for an HDD to succumb to a head crash, a sudden power failure, wear and tear, electronic failure, physical shock, corrosion, poorly manufactured platters and heads, etc.

HDD uses magnetic storage. Therefore, if the disk comes in close contact with powerful magnets, the data stored can get corrupted or damaged.

Storage capacity of HDD

The storage capacity of the HDD is up to 20 TB.

Defragmentation in HDD

Since HDDs have magnetic platters to store data, the input-output operations occur at a faster rate when all information is stored in the same place within the disk. In situations where a particular file’s data is stored in different sections of the HDD disk, the speed of input-output operation reduces. This is because the HDD disk has to spin for different parts within the disk to come in contact with the read/write heads. Generally, there may not be enough available space to store all the information in a file. This situation results in the fragmentation of HDD. Fragmentation can slow down the processing of HDD. Periodic defragmentation is required to keep HDD from losing speed.

Components and operation of HDD

A regular HDD drive contains the following parts,

  • Platters: A non-magnetic material flat circular disk, coated with a fine layer of magnetic material. Information is recorded on this disk.
  • Spindle: This component is responsible for holding platters.
  • Read/write heads: These exist on top of the disk. They can detect and augment the magnetization of the materials that exist directly under them.
  • Motors: These are used to spin the platters at high speeds for data transfer. A typical HDD consists of two motors. One of the motors is used to spin the disks, and the other is used to position the read/write assembly. When the platters are rotated past the read/write heads, information gets recorded in the platter.

Main Differences between SSD and HDD (in Points)

  • SSD is an acronym for solid state drive. HDD is the acronym for hard disk drive.
  • SSDs use memory chips for storing and accessing information. HDDs use spinning platters.
  • SSDs are faster than HDDs.
  • SSDs do not move parts, hence they are quiet. HDDs use moving parts, hence they are noisy.
  • SSDs do not generate heat. HDDs generate heat when operating.
  • SSD requires low power to function. HDDs use more power to operate.
  • SSDs are not affected by fragmentation. HDDs are affected by fragmentation of data and need to be defragmented periodically.
  • SSD disks are lighter than HDD disks.
  • HDDs have more storage capacity than SSDs.
  • HDD sequentially transfers data. SSDs transfer data non-sequentially.
  • SSD is more durable than HDD disks.
  • SSD has a shorter lifespan compared to HDD.
  • SSD disks are mostly used for storing operating systems, frequently used files and gaming apps. In contrast, HDD disks are better suited for storing extra data like documents, movies, and photos.


To sum up, SSD and HDD have their own merits and demerits. Comparatively, SSDs are faster, more durable, quieter, and smaller than HDDs. HDDs have a longer lifespan. Depending on the need you can choose between the two. If you want extra space for storing your files like documents, movies, and photos, choose HDDs. Alternatively, if you are planning on buying laptops for companies choose SSD. SSDs are also the better option for a gamer.


  • https://www.avast.com/c-ssd-vs-hdd
  • https://www.avast.com/c-what-is-ssd

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"Difference Between SSD and HDD." Diffzy.com, 2024. Mon. 04 Mar. 2024. <https://www.diffzy.com/article/difference-between-ssd-and-hdd-1341>.

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