Difference Between HDD and SSD

Both HDD and SSD are known to be the non-volatile type of storage hardware devices used by computers, laptops, etc. in order to store data and programs. The significant difference between HDD and SSD lies in the technology used by them to store the data. Basically, both the storage devices use distinctive technology for storing as well as retrieving the data.

HDD is known to be an electromechanical device that contains moving disks called platters to store the data magnetically. On the contrary, SSD is a solid-state device that is free from moving disks but contains integrated circuits within which the data is stored.

HDD is an ancient technology that is present within the host for storing software programs and data while SSD is the outcome of technological advancement after the arrival of semiconductor chips.

Content: HDD Vs SSD

  1. Comparison Chart
  2. Definition
  3. Key Differences
  4. Conclusion

Comparison chart

Basis for ComparisonHDDSSD
Full formHard Disk DriveSolid State Drive
Introduced in19561976
GeometryElectromechanical device with moving disk (Platter), spindle, metallic case.Solid state device with electronic units such as integrated circuit.
LatencyHighComparatively low
Storage capacityMore physical space offered (250 GB to 20 TB)Comparatively less physical space offered (120 GB to 30 TB)
Energy consumptionHigh Low
Cost InexpensiveExpensive
DurabilityLess durableComparatively more durable
Read/Write timeLongShort
SpeedSlow (measured in RPM i.e., revolution per minute)Fast (measured in MB/s)
Noise productionMoreLess in comparison to HDD.
Shock resistivityLessMore
Effect of magnetismExistNot exist
Size and WeightLarge size and heavy device.Small size and light-weight device.
Heat production MoreComparatively less
Major useFor storing user’s data like image, files, videos, audios, etc.For storing software programs.

Definition of HDD

HDD stands for the hard disk drive, which is a mechanical device that is used for storing data. In HDD, data is stored permanently within the circular disk called a platter by inducing magnetic changes within the disk. The data on the disk is read and write using the arm that contains several heads (transducers) and according to the motion different data present in the disk is accessed.

hard disk driveHDD is known to be an old-school method for storing data and information on a permanent basis. Due to the components involved in its fabrication, it is generally suitable for storing such kinds of data that include less frequent accesses, like images, videos, audios, business files, etc.

The read-write operation within the device takes place with the help of a disk head through which the pattern on the disk is either sensed (read operation) or a change in the pattern is induced (write operation).

The standard sizes for HDD are 3.5 inches and 2.5 inches for desktop and laptop respectively. The spinning speed of the one present on the desktop is around 7200 rpm that can store up to 6 terabytes of data. While that of the one present in a laptop is around 5400 rpm that allows storage of up to 2 terabytes.

With the advancement in technology, memory chips have replaced magnetic disks that have improved energy consumption and shock resistivity.

Definition of SSD

SSD stands for a solid-state drive that is flash-based storage like RAM which includes electronic components but no moving mechanical parts for storing data and information. It is a semiconductor device that offers a longer lifespan than HDD with noise-free and reliable operation.solid state drive
It provides the facility to access the data at a faster rate because of the technology involved. SSD consists of several NAND memories that are connected with each other through 8-bit buses referred to as channels for connecting the memories with the controller. The use of multiple flash memories facilitates providing more storage space along with providing better read/write performances.

The access to the various memory channels is scheduled by the memory controller. The memory controller helps in maintaining proper interfacing between the host and the memories. Also, it efficiently manages the data transfer.

One of the factors that limit the use of SSD in laptops and desktops is its high cost. The is so because, for the same storage capacity, SSD is around 3 to 4 times more expensive than HDD. However, due to its various advantageous factors, NAND flash memory-based SSD has gained wide importance as secondary memory in modern computing systems.

Key Differences Between HDD and SSD

  1. The HDD is an electromechanical device that consists of moving machinery within which data or information is stored magnetically. As against, SSD is a solid-state device that consists of electronic components such as integrated circuits for storing the data.
  2. The storage capacity offered by the two also acts as a key factor of differentiation between HDD and SSD. HDD offers physical space of around 250 GB to 20 TB, this is comparatively higher than the one offered by SSD which is nearly around 120 GB to 30 TB.
  3. Due to the presence of spinning disks (platter) in the HDD, the chances of wear and tear are more in it due to the risk of mechanical failure. While as SSD contains static parts, therefore, they are comparatively less susceptible to frequent wear-outs.
  4. The mechanical parts of the HDD make it more sensitive to shocks in comparison to SSD. Therefore, it is said that SDDs are more shock-resistant than HDD.
  5. The noise produced during operation is less in the case of SSD due to no moving components in it. But HDDs during operation generate a considerable amount of noise.
  6. Due to the presence of magnets, effect of magnetism exists in HDD. Thus, these are more prone to undergo damage or data corruption when present close to magnets than SDD which is free of magnetic components. This makes SSD comparatively more reliable than HDD.
  7. As comparatively more energy is required by devices that have moving parts than the one that consists of non-moving parts, thus, HDD consumes more power in comparison to SSD.
  8. The whole operation of HDD shows dependency on spinning platters and magnetic drives thus start-up speed of HDD is comparatively slower than SSD. More specifically, according to Intel, SSDs offer 8 times faster-operating speed than HDD.
  9. The two types of data storage devices use different technologies for read/write operations. HDD includes a sequential manner of data transfer while the same is random in SSD, thereby allowing the transfer of data to take place at a faster rate.
  10. HDD is a bulky device that is large in size due to the type of components it holds. However, SSDs are light-weight devices that are small in size.
  11. When the cost of the two devices is considered then it is noticed that as SSD is more technologically advanced than HDD and so SSD is comparatively expensive than HDD.
  12. During the motion of the components, the production of heat is comparatively more than the case of static components. Due to this reason, the heat produced within an HDD is higher than the one generated in SSD.


Thus, from this discussion one can conclude that both HDD and SSD are non-volatile storage devices that show significant variation in terms of the way they are fabricated as well as operate. These factors give rise to several differentiating points between the two in terms of cost along with storage space and efficiency in operation.

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