ssd vs hdd

The difference between HDD and SSD | HDD vs SDD


When comes to static storage or secondary memory in a computer. Computer stores data on a hard disk. A hard disk comes with multiple storage capacities and types. There are two main known types Hard disk drive(HDD)  and Solid State Drive(SSD).  Each option has its own cost and performance metrics. Which option is suitable for a user depends on the budget and performance requirements.

In this tutorial, we will describe each type and a detailed comparison between the two.

What is HDD?

An HDD type of storage can be internal or external to a computer. When internal, it connects to the motherboard using data buses, for external it uses USB connectivity.  There is a spinning disk there stores data magnetically and a moving head for reading and writing data.

There are magnetic circles each circle divided into basic units called sectors.  When a program needs to access the data, heads move to that block or sector and reads or writes.

If you consider HDDs over SSDs, they are legacy storage technology. The existence of Hard Disk Drives is before the SSD was first invented.  At a broad level, they cost-effective for storing any kind of files.  Comes in two sizes, 3.5 inches, for desktops and 2.5 inches for laptops.

What is SSD?

If you are a student of electronics, you might hear about solid-state devices.  In this, a device is in the form of an electronic chip.  In contrast to the HDD, it does not have any moving part. That brings higher speed by eliminating the time needed to spin the disk and head moment.

Till now per GB storage in SSD is costing higher than HDD. But with the advancement in technology, SSDs are getting cheaper day by day.  A laptop with SSD will cost more, but it can be faster and slimmer.

What are the differences (HDD Vs SDD)?

Variable Access Time –  With the traditional HDD, the data access time depends on the location of data over the disk.  If it’s close to the head, read will be faster.  For example, if a file is not stored at a contiguous location, the disk and head will move multiple times.   While with SSD this is not the case.

Hardware failure –  The HDD has the mechanical parts, if there is a slight alignment problem or if a disk falls from a height. There are high chances of damage as compared to the other.

How SSD is advantageous-

  • Data Access speed in SSD – Unlike the HDD,  the access time for data is the same either it is data is contiguous or not. This results in no need for defragmentation while storing data.
  • Easy to Carry – You can carry an SSD easily without worrying too much bout the damage while moving.   Do not have movable parts, so lesser are the chances of damage by the vibrations on the move.
  • Power Consumption– SSDs do not have mechanical parts that enable them to consume lesser power as compared to HDD.  Suits well in computing equipment for longer battery life.
  • Lesser Noise – You might hear a noise inside the computer while accessing a file. It’s because the mechanical components create friction in HDD.  SSD does not have such a thing, so no noise.

Is there any disadvantage of using SSD?

Till now we have seen that SSDs are better than in all aspects of data storage.  Both can store a large amount of data but SSD performs better. So is there any disadvantage? Yes, nothing comes free, so better experience more cost. SSDs are costlier than HDDs. It can be 4 times more expensive. A beginner with a lesser budget opts for HDDs.

Another thing is that SSD is based on NAND technology.  It uses integrated circuits that use NAND gates for storage.  When a block of data needs to write. All data is rewritten to the memory.  It is unlike the HDD, where only a block/blocks of data is written.