What features should you compare and look at when you have to buy a disk to add to your PC, internal or external

PC disk types Internal memory is the component of computers where all the data that needs to be kept is saved even when we turn off the machine (unlike RAM memory, where the information is lost when the machine is turned off). The data can be: music, photos, documents, games, videos, films and so on.

Internal memory is present inside the PC but we can also find it on the market external disksdesigned to store data outside the PC and be able to carry it around with us, using a simple USB cable to connect our personal memory to any computer or USB-compatible device.

After making a list of things to know before buying a computer and how choose the LCD monitor to purchasewe will show you in this guide all the differences between disks, SSD, M.2 and mechanical disksshowing you what the advantages are in having a certain disk type such as internal storage and how Make the most of external drives.

READ ALSO: Buying a network NAS storage: what is it for and how much does it cost

Hard disk, SSD o M.2?

The first subdivision to make is whether to focus on a mechanical disk, a traditional SSD or the new M.2; it is worth learning the differences well, since they are very profound between the various types of discs.

L’mechanical hard disk (or HDD) is much more capacious and costs significantly less, but has lower reading and writing speeds and is sensitive to mechanical and physical stress.

And SSD SATA it has no mechanical components (there are only chips where the data is saved), it has much higher reading and writing speeds and prices are dropping quickly, even if they are still more expensive than mechanical disks.

The SSD M.2 NVMe they are the direct evolution of SSDs: they come as small, thin and long memory cards that can be added directly to the motherboard, without having to use a cable. They allow you to reach very high speeds but have a higher cost, as well as requiring the latest generation M.2 NVMe slots to be able to be used to great effect.

To store data, great speed is not usually required, so to store only data (therefore without an operating system) we can focus on a large hard disk. and transfer speed is a priority, we will have to buy an SSD or an M.2, well aware that the costs are significantly higher.

For further information we can read our guides on differences between types of SSD drives come on how to use M.2 SSD for PC, how to mount it and where to buy it.

Disk partitioning for PC

As already mentioned, disks can be internal and external; based on their type, the dimensions and type of connection that can be used change.

1) External disks

I drive esterni they can be connected to any PC simply by connecting a cable USB. These drives are portable and incredibly simple to use, since you just need to connect with the cable and they are recognized by the system, with all their space immediately available in This PC o Computer resources.

External drives usually do not require additional power to operate, as the USB 3.0 cable (or later) meets the power needs of any type of disk. Regarding size there are two typesof external drives:

  • 2.5 inch driveeasily portable even in your jacket pocket, which are powered via the USB cable.
  • 3.5 inch driveheavier and less easy to carry around, powered by an independent electrical socket.

This latter format is now disappearing, at least when it comes to external drives, in favor of disks of smaller size and weight. The choice between one or another type of external hard drive depends on your personal needs regarding portability and storage space factors.

Another parameter on which to base the quality of a hard disk and on which the price can depend is the rotation speed, the higher it is the faster the data will move. Rotation speed does not exist on SSDs and M.2, since there are no mechanical components.

For further information we can read the articles on The best external disks for backups and on Best Portable External SSDs.

2) Internal disks

If you want increase the storage capacity of the desktop computer (or to replace a broken or old disk) it is better to buy an internal hard disk, to be placed in the space reserved for disks inside the PC case (usually suitable for hosting 3.5-inch drives).

It can act as a secondary hard disk (if there was already a disk) and can be used for Windows backups, to save files, documents, games, films, programs and so on. Once in position, simply connect the SATA cable to the appropriate slot and the power cable (available among the cables that emerge from the power supply or can be connected as an auxiliary cable on modular models).

Compared to external disks, therefore, internal disks always require auxiliary electrical current to function, supplied via a separate cable. If the hard disk is to be mounted inside a laptop PC, the dimensions also change: you will have to choose a 2.5-inch hard disk to fit it into the appropriate slot (replacing the old disk).

For laptops you can find both mechanical disks and 2.5-inch SSDs; SSDs can also be mounted without problems on fixed PCs, given that the cables to be used are the same (and we don’t even have to worry about arranging or placing the disk, given the absence of mechanical parts).

On the new notebooks we find it dedicated slot for M.2 NVMe: this allows, for those who know how to disassemble computers (which is not always possible nowadays), to always upgrade the internal memory, changing the drive and replacing it with a new, larger and/or faster M.2.

For further information we can read our article on how to mount an SSD instead of the hard disk on a laptop.

3) Multimedia or network disks

The Hard disk multimediali they are ideal for saving films and sharing any type of data with a PC, with a TV or with the entire network (if connected to your home router).

It also happens that in electronics stores you can find multimedia stations without a disk inside and, in this case, you need to buy a normal computer hard disk to make the most of it. These disks have the same performance as simple disks combined with management software, a remote control system (with a remote control) and an internal data server to make all the files and disk space available to the entire network, acting as a network disk.

They can be connected either via USB cable or via Ethernet cable (in the latter case to be connected to the home router). We can find the best Discs media players eh best network drives directly online, ready to be connected to the network and viewed from any device that supports network file sharing (using SMB or Windows network sharing).

Alternatively we can also purchase a USB disk slotinsert any type of disk you prefer and connect it to the modem usb damas seen in the guides above how to connect network disk to the FRITZ!Box about are how to connect a disk to the router to share files over the network.


The choice of the type of disk and how to use it obviously depends on our needs. For internal drives that must host the operating system or programs we only use SSD and M.2, while for files we can also use a fairly fast mechanical disk (as a second disk on a fixed PC); on laptops we only use large SSD or M.2.

For external USB disks we use SSD if we want speed, HDD if we want more storage space; if instead we want a network disk or a multimedia disk we can focus on HDDs or a USB slot, personally installing the disks we want to use.

On the same topic we can read the guides on how to check the status of the disk (HDD and SSD) with tests on health, performance and speed come on what not to do on a computer with an SSD.


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