By Teresa / Last Updated June 16, 2020


In the past, the standard for you to choose the best PC storage is selecting the highest-capacity hard drive. However, life isn’t always so simple, recently, the rise of SSD drives have significantly changed the situation. That makes the consumers feel puzzled about which one to choose. So before you go shopping, you will consider a very basic question: SSD and HDD which one is better? Besides, many users would like to replace HDD with SSD in their PCs, but it is better to get them across first. Follow this guide, the detailed differences between SSD and HDD will help you to make an advisable decision.


HDD has been the default storage component in desktop and laptop PCs for many years. HDD applies the basic nonvolatile storage on computer to store your data. HDDs are metal platters with a magnetic coating that stores your data. When the platters are spinning in a hard drive enclosure, there is a read/write head on accessing data. You can find many difference on SSD vs HDD performance.

Hdd Vs Ssd

For SSD, it uses nonvolatile storage as HDD. But instead of a magnetic coating on the top of platter, the data is stored on memory chips that help you retain the data even when there is no power. Besides, there are no moving parts in SSD. Instead, the SSD has an array of semiconductor memory organized as a drive that uses integrated circuits instead of magnetic or optical media.

Differences between SSD and HDD

In this section, we will show you the differences between SSD and HDD in terms of their components, write speed, reliability and more.

1. SSD vs HDD components

An HDD contains a spindle that has one or more flat circular disks named platters made from a non-magnetic material and coated with a thin layer of magnetic material. For a typical HDD, there are two motors, one for spinning the disks and another for read/write head. When data rotates the read/write heads, it is written to a platter.

Compared with HDD, SSD uses microchips and there is no moving part. Furthermore, SSD components contain a controller that executes firmware-level software that is one of the most essential factors for SSD performance. Moreover, you can easily make SSD in RAID array while it is hard for HDD. These entire differences make SSD has more advanced features.

2. SSD vs HDD write speed

Standard HDD drives have platters that are covered in a magnetic coating. When they rotate at high speed, then drive heads move across the platters in order to alter the magnetization of the material beneath to record data. However, SSD can offer much faster read and write speed than HDD. This incredible speed difference is due to SSD doesn’t need to spin up the drive platter or move drive heads, the data can be read from the near drive instantly. Due to this advantage, many users plan to only install OS on SSD.

3. SSD vs HDD reliability

Hard disk failures which may make your data lose happen all the time, especially for HDDs. Why do HDDs fail? Because all HDDs have fragile mechanical components, which makes them prone to suffer wear and tear. However, SSD doesn’t have this problem because it has no moving parts. Furthermore, no mechanical materials make SSDs be immune to physical vibration and extreme temperatures.

4. SSD vs HDD defragmentation

HDD has magnetic platters to store data, so when data is stored sequential on the disk, IO operations (reading from or writing to the disk) will work much quicker. However, when data isn’t stored sequential on the disk, IO speeds are decreased as the disk needs to spin for different regions of the disk in order to contact with the read/write heads.

But in fact, there is not enough serial space to store the whole data in the same place. This causes fragmentations for HDD. Therefore, defragmentation is necessary for HDD at regular intervals. For SSD, there is no such physical restriction for the read/write head and the location of the data on the disk doesn’t affect its performance. So defragmenting SSD is unnecessary.


From the comparison between SSD and HDD, you can see there are many advantages of SSD. In addition, you can learn more about SSD performance with the help of SSD benchmark software. In order to make your computer have good performance, you can install your OS on SSD drive. If you want to do like this, how can you migrate your present OS from HDD to SSD? Fortunately, there is the third-party software AOMEI Partition Assistant which has a feature called Migrate OS to SSD can help you.