What is Solid State Drive?

A Solid State Drive (SSD) is a modern storage device. The storage is non-volatile in nature thus it retains data even if the power is off. As the name suggests solid state drive, the drive does not contain any moving mechanical parts like HDD.

SSD makes use of flash memory and is capable of accessing all the cells of the memory at a consistent speed. SSD offers many benefits over our conventional HDD such as its faster, more durable, several factor forms, consumes less power, and makes no noise at all.

Let us discuss more features of SSD in the section below.

Solid State Drive in Computer

  1. Why do we need SSD?
  2. How Does SSD Works?
  3. Types of SSD
  4. SSD Vs HDD
  5. Advantages & Disadvantages

Why do we need SSD?

SSD is now a day rapidly replacing hard disk drives though it performs the same basic function as HDD. This is because it offers several advantages over the conventional magnetic hard drive. Above all SSD is significantly faster than HDD.

So eventually it loads the operating system much faster which thereby speeds up the booting process of the computer. It even makes accessing or storing any file on the computer faster.

Solid State Drive

SSD also consumes less power as compared to HDD. As SSD is a flash memory it does not consist of any moving parts such as header, or rotational platters so even if your system gets shaken while operating your data is still safe.

However, SSD offers much more benefits than HDD we will discuss them in the section ahead.

How Does SSD Works?

We use SSD for storing data. But unlike HDD it does not contain any moving parts such as a rotational platter or moving head. Instead, like RAM it uses flash memory to store data. But unlike RAM which losses data as soon it losses power; SSD retains data even if power is off. The flash memory data can be written, transferred, and erased electronically.

SSD is made of several semiconductor chips that are integrated into a circuit board. Each semiconductor chip is made up of a grid of electrical cells. These grids of cells are divided into sections that we refer to as pages. These pages are grouped to form blocks. In SSD each block can be accessed at a consistent speed.


SSD writes data only to empty pages in the block but it does not erase page by page. Instead, it erases data in unit blocks i.e., when enough of the pages in the block is not in use. It copies the entire block data to the memory and erases the entire block. Now copy back the data of pages that were still in use, leaving unused pages blank.

When SSD has been newly installed all the blocks with blank pages, so, it starts writing to those pages with a blazing speed. But over time it is left with blank pages scattered throughout the blocks.

How Processor Writes Data in SSD?

Now, whenever new data has to be written in SDD the processor has to follow the following steps.

  1. Identify a block that has enough pages that are not in use.
  2. Identify the pages that are still in use in the block.
  3. Copy the entire block to memory and reset every page in the block as blank.
  4. Rewrite the data of pages that were in use into the freshly reset blocks.
  5. Write new data to blank pages of the reset block

Types of SSD

We can classify SSD based on their interface. So, there are two types of SSDs SATA SSD and PCIe NVMe SSD. SATA is specially designed for average users as it is more affordable and offers a good performance for almost all common applications.  PCIe NVMe SSDs are four times faster than SATA SSDs and specially designed to perform heavier work such as gaming, video editing, large file transfer, etc.

Types of SSD

Serial Advanced Technology Attachment (SATA SSD)


The 2.5 SATA SSD is an SSD specially designed for desktop computers. The processor can access data from this SSD at the speed of 600 Mbps.


M.2 SATA SSD comes in flat and compact card format and is specially designed for mobile devices and laptops. It has the same access speed as that of a 2.5 SATA SSD i.e.600 Mbps. Although it can also be used on desktop computers if your motherboard has the slot for the same.

Peripheral Component Interconnect Express (PCIe SSD)

The PCIe SSD has comparatively greater bandwidth which gradually increases its speed. PCIe SSD is the fastest SSDs. Thus, they are preferred by user who wants the fastest performing speed such as gamers. These fastest types of SSDs are even more expensive.

M.2 Non-Volatile Memory Express (NVMe) SSD

In NVMe, the term express reveals that the bandwidth it drives uses the PCI express bandwidth instead of your SATA bandwidth. NVMe SSDs


Comparison PointsHDDSDD
Consist ofSpinning platters of magnetic drives, read write headFlash memory chips integrated into an electric circuit
SpeedComparatively slowFaster
CostLess expensiveComparatively expensive
SizeHDD comes in large capacityComparatively less capacity
DurabilityLess durableMore durable
Form factorsThere is a limitationNo such limitation
NoiseAs it has mechanical parts it makes noiseNo mechanical parts no noise at all

Advantages of SSD

  • SSD are comparatively faster than HDDs.
  • As it has no mechanical moving part it consumes less power than HDD.
  • SSDs are more durable.
  • SSD is more compact than HDDs.
  • Lower latency.
  • Do not make noise.

Disadvantages of SSD

  • More expensive than HDD.
  • Comes in less capacity
  • They have a shorter life span as compared to HDDs. The cell of the flash memory of SSD decay with each writing cycle.

Thus, we can conclude that SSD is the fastest non-volatile storage device. It has higher data transfer speed and offers many benefits over HDD. But gradually the performance of the SSD decreases.

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