Choosing the Right Hard Disk Drive

A hard disk drive is a non-volatile memory hardware device that permanently stores data from a computer or server. Hard disk drives keep the stored data even when they are turned off.

The most common technology uses fast rotating magnetic platters. These are traditional HDD (hard disk drives). They are increasingly being replaced by SSDs, which are solid state semiconductor memory devices.

View hard disk drives

  • How to choose a hard disk drive?

    Toshiba hard disk drive

    Several criteria are important to consider when choosing a hard disk drive:

    • Do you need an internal or external hard drive?
      • Do you need a large storage capacity? If so, you will want to choose an internal hard drive.
      • Do you need a portable hard disk drive? If so, an external hard drive will be the best option.
    • Which format should I choose for my hard disk drive?
      • The standard formats, defined according to the size of the platters, range from the largest for older discs (19 inches) to the smallest (1.8 inches).
    • What data storage capacity should I choose?
      • This will depend on your storage needs and budget. The maximum capacity currently available on the market is 16 TB. Be careful: technology is changing fast. Every year, new and improved technology is used to increase the capacity of hard disk drives.
    • What level of performance will I need? This depends on:
      • the rotation speed of the platters (generally between 5,400 and 15,000 rpm) The higher it is, the better the disc throughput
      • the latency (rotational delay)
      • the positioning time (the time it takes for the head to reach the cylinder)
      • the time it takes to transfer data from the disk to the computer
    • What type of interface should I choose?
      • The choice of interface depends on the internal architecture of the PC.
      • The choice of interface has a significant impact on the data transmission speed.
      • The main interfaces currently available on the market are the following: SCSI, IDE, Serial ATA, SAS, Fiber-Channel
    • Should I choose HDD, SSD or SSHD?
      • The HDD (hard disk drive) stores information on rotating magnetic disks, the data is read by moving read/write heads located on either side of each platter.
      • The SSD (solid-state drive) consists of flash memory chips and has no mechanical components.
      • The SSHD is a hybrid hard disk drive that contains magnetic elements of the HDD and a SSD type flash memory.

    Selection criteria

    • Internal/external
    • Format
    • Capacity
    • Performance
    • Interface
  • Should I choose an internal or external hard disk drive?

    Most hard disk drives are internal. However, stand-alone devices called external hard drives also exist. They allow you to increase your available storage space. Both types of hard disk drives have their advantages and disadvantages. Below is a summary to help you choose the best option

    Toshiba internal hard disk drive

    Internal hard disk drives

    These are the most common hard drives.
    They are located in the computer and can therefore only be used by it.
    There are 2 types of internal hard drives: HDD (which work with rotating disks) and SSD (flash memory).


    • They are always connected to the computer, making backup operations and updates easier.
    • Their data processing is faster because they are directly connected to  the computer’s motherboard.


    • They are not “plug and play” and require actions to be taken in order to move them from one computer to another.

    Seagate external hard drives

    External hard disk drives

    • These are portable stand-alone devices that allow data to be stored outside the computer.
    • They are often located in a protective case and connect to the computer via USB or FireWire.
    • Some external hard drives can even connect to wifi.


    • They are very light and portable so they can be transported easily.
    • They are “plug and play”: all you have to do is plug them in and they work.
    • They are very convenient for transferring data.
      They can be connected to several computers without needing to format.


    • They generally have a lower storage capacity than internal hard disk drives.
    • They are also slower because data is transmitted by cord.
    • The cord is more likely to be damaged if you plug your hard drive in and out often.
    • As they are portable, they are more likely to be exposed to shocks and it is also easier to lose them.
  • Which interface should I choose for my hard disk drive?

    There are different hard disk drive interfaces for connecting a hard disk drive to your computer, depending on whether your intended use is personal or professional.

    For personal use and storage

    PATA (Parallel ATA) or IDE (Integrated Drive Electronics).

    • This is one of the oldest disk interfaces (1980s).
    • It uses parallel communication.
    • The connection is made using 40-wire or 80-wire connector cables.


    • A PATA cable allows you to connect 2 hard disk drives at a time.
    • Inexpensive technology that has been tried and tested.


    • The maximum length of cables connecting the hard disk drive to the motherboard is limited (46 centimeters or 18 inches), which can be limiting in terms of where you place your hard drive.
    • The speed (66/100/133 MB/s) is lower than that of SATA.

    SATA (or Serial AT Attachment) is the interface launched in 2003 that succeeded the PATA standard. It uses serial signalling technology to store data.


    • The speed (150/300/600 MB/s) is higher than that of PATA. This means that large programs and documents are loaded more quickly.
    • SATA cables are longer (up to 1 meter) allowing for more flexibility in where you choose to place the hard drive.
    • The cables are also thinner, which results in better air flow in the PC casing, reducing heat build-up within the computer.
    • It is possible to connect several SATA hard drives because there are 4 to 6 SATA ports on a motherboard (compared to 2 PATA connections on a PATA motherboard).


    • SATA hard drives often require a special device driver to be recognized by the computer.
    • A SATA cable can only connect one hard disk drive at a time (compared to 2 per PATA cable).

    For professional installations and servers

    For professional use, it is recommended to choose hard disk drives with a SCSI (Small Computer System Interface). These offer higher performance (transfer rate, operability, multi-user mode) useful for dynamic storage of corporate information on servers.

    Among the technologies using SCSI commands is the SAS (Serial Attached SCSI) interface.


    • SAS hard disk drives are faster and more reliable than SATA ones.
    • They allow data transfer of up to 6 Gb/s.
    • They can be used 24 hours a day,  7 days a week.
    • They have an operating capacity of 1.6 million hours at an operating temperature of 45°C.


    • A SAS hard disk drive is at least 10% more expensive than its SATA equivalent.
    • It offers less storage capacity.
    • It uses a lot of energy.
  • Should I choose an HDD or SSD?

    Delkin Devices SSD

    The standard hard disk drive HDD is the main storage device for computers because it is inexpensive and offers large storage capacities.
    However, SSD (solid state drive) is increasingly replacing the classic HDD because it has undeniable advantages (more durable, without moving parts, etc.).
    But be careful, despite its many advantages, SSD is not always the best solution. It all depends on what you’re looking for.

    Below you’ll find a table summarizing the main characteristics of each option. This will help you make the right choice.

    Characteristics HDD SSD
    Data access speed 20-40 milliseconds 0.1 millisecond
    Transfer speed <200 Mb/s >500 Mb/s
    (Form factor)
    3.5” for desktops and servers, and 2.5” for laptops Available in 2.5”, 1.8” and 1.0”
    Capacity Up to 16 TB for a reasonable price <3 TB
    Energy consumption Significant as there are several parts to be rotated Low, which also increases battery life
    Reliability Presence of moving parts that wear out and therefore can make the disk unreliable in the long term. Flash memory ensures better disk reliability
    Heat More significant due to moving parts, which can lead to components wearing out Low
    Noise Noise from the rotating platters and read/write heads None
    Magnetism Powerful magnets could erase the data from the disk because this technology is based on magnetism No impact
    Price Low High

    It should be noted that a new type of hybrid hard disk drive has been developed. The SSHD is a hybrid hard disk drive that contains magnetic elements of the HDD and a SSD type flash memory.

  • Which hard drive sould I choose for NAS?

    One of the latest big changes in the world of hard disk drives is undoubtedly the rise of Network Attached Storage (NAS) servers. They are designed to respond to the explosion of big data and the consequent growing storage and archiving needs of companies.

    A NAS server allows information to be stored on a local network, accessible only by authorized users. It acts like a private cloud.

    It has many advantages:

    • It is more reliable.
    • Several users can access the hard drive at the same time whenever.
    • Its storage space can easily be increased (with scale-out or cluster storage).

    NAS HDD or standard HDD?

    While there are hard disk drives designed specifically for NAS servers, a conventional HDD works very well in a NAS architecture as well. However, NAS hard disk drives have more advantages:

    • They use less energy and as such have a longer battery life.
    • They have better control over their use of electricity during rest periods (even though the NAS server is running all the time, its hard disk drives are not constantly in use).
    • They are 30% more reliable than conventional hard disk drives.
    • They have high data transmission rates (up to 7,200 rpm), which reduces vibration.
    • They offer storage capacities of up to 16 TB.

    Whatever your choice, you will have to take into account several constraining factors before choosing the hard disk drives for your NAS architecture:

    • Energy: hard disk drives operating 24 hours a day, 7 days a week (for example in the case of video surveillance) will always be on, so opt for a more energy-efficient model.
    • Heat: Make sure that the disks can withstand some heat, especially if you want a compact system with low ventilation.
    • Noise: for NAS servers that you want to be discrete, you will need to look at the number of decibels of the disks when in operation and inactive.
    • Vibrations: a NAS server includes several hard disk drives, the vibrations of one can affect the others.
    • Speed: If you want your NAS server to have less noise and vibration and consume less energy, you should choose low-speed models (<6,000 rpm).
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  • digitalpower says:

    Thank you So much for this Informative Blog. Learned Many the new things which i dont know till now. Please keep Posting more Blogs like this one. Thanks Again.

  • Ultra-320 68Pin SCSI HDD says:

    Such a very brilliant blog. It is packed with facts in able for the costumers in choosing the right hard disk drives. A must read article.

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