Adding an Internal Hard Disk Drive to Your Computer

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Adding an Internal Hard Disk Drive to Your Computer

Computers, desktops, as well as laptops that were manufactured even until a couple of years ago did not come with too much storage space in terms of the hard drives they carried, although this has changed considerably now. People, who use older machines, it has been noticed, need to look for additional storage space sooner or later, which normally comes in the form of an internal hard disk drive or more. Besides, hard disk drives do crash from time to time, and such instances require computer users to look for replacement internal hard disk drives.

Adding an internal hard drive means shopping, and while shopping for an internal hard disk drive can be accomplished in regular brick-and-mortar shops that deal in computer peripherals, turning online to websites, such as eBay, is also an option. In either case, knowing just what to look for before buying an internal hard disk drive is important, starting from whether it's required for a desktop or a laptop. Other aspects that also require buyers' attention include the interface, storage space, speed, and cache size. Learning just how to remove and install an internal hard disk drive should follow.

Desktop or Laptop?

This is the first aspect that requires a buyer's attention, because the physical size, or form factor, of internal hard drives used in both can vary. Until not so long ago, desktops typically used 3.5-inch hard drives, and laptops made use of 2.5-inch hard drives. This, however, has changed with the introduction of slim and all-in-one computers, where most of these use 2.5-inch hard drives. Some manufacturers now include 2.5-inch cages in their systems, enabling users to replace existing 3.5-inch hard drives with 2.5-inch ones. Older desktop models use 5.25-inch hard drives, which can still be found as well. Buyers who have computers that use 5.25-inch hard drives have the option to replace them with 3.5-inch variants, which is done through the use of special rail spacers. Certain laptops use 1.8- inch hard drives, and servers typically use 3.5-inch alternatives.

The interface used can also vary in accordance to the application; while desktops use IDE and SATA interfaces, laptops use IDE, SATA, and SCSI, and servers use SATA and SCSI.

Internal Hard Disk Drive Interface

There are three basic ways through which a hard disk drive can connect to a computer, which include: ATA, SATA, and SCSI.


ATA stands for "advanced technology attachment", and is also referred to as IDE, PATA, and ATAPI. This was pretty much the standard before SATA came into being, and it continues to be an affordable alternative. However, this interface alternative offers a cable length with a limited standard that stands at 46 cm. Connecting an ATA interface hard drive can be a little challenging.


SATA stands for "serial advanced technology attachment" and is definitely the more commonly used hard disk interface in today's world. An increasing number of power supply alternatives now offer SATA connectors, and a majority of motherboards in today's computers come with inbuilt SATA controllers as well as SATA cables. While motherboards in the coming future are bound to incorporate SATA technology, they may well do without ATA.

SATA technology has now become cheaper than its predecessor, it is easier to connect, and its narrower cables offer better heat dissipation. When it comes to transfer rates, although file transfer can be faster in comparison to ATA, this difference can be marginal in a number of instances.

The evolution of SATA technology has led to three versions being released until now, including: SATA ISATA II, and SATA III, which is something that needs your attention if you decide to choose SATA. The difference, in essence, lies in the transfer rates, as can be seen in the table below.


Transfer Rate


1.5 Gbit/s - 150 MB/s


2.0 - 3 Gbit/s - 300 MB/s


3.0 - 6 Gbit/s - 600 MB/s

The enhancements made in SATA III were aimed at providing a higher quality of service for high priority interrupts and video streaming. In addition, SATA III continues to remain compatible with SAS, which includes SAS 6 Gbit/s.


SCSI stands for "small computer system interface" and is also commonly referred to as scuzzy. Typically used in servers and industrial applications, and not so much in home PCs and laptops, this interface is not widely supported. Its advantages include faster transfer rates, better flexibility and scalability, backward compatibility, reliability, and suitability for moving and storing large volumes of data. Its drawbacks include more heat and noise, the cost factor, and the fact that there are various types of SCSI interfaces.

Storage Space

Internal hard disk drives come with varying capacities or storage space, and the more storage space, the more expensive the hard drive. Storage capacity of hard drives have increased considerably over the recent past, and while 40 GB and 80 GB hard drives were quite common until five years ago, buyers can now find hard drives that offer up to 4 TB of storage space with relative ease. What you should bear in mind when deciding on storage space is that a number of older computers, or those that use Windows XP, can have problems recognising the complete availability of space with hard drives that exceed the 2 TB mark. How much storage space you should choose depends on the hard drive's intended usage. If you intend to run basic programs on your computer, you can choose 500 GB, and if you intend to store music, films, and games, then you should ideally look beyond 1 TB.


This aspect needs your attention because longer transfer rates can slow down a computer significantly, especially when transferring heavy files. Hard drive speed is typically displayed as RPM, or rotations per minute, and all 3.5-inch SATA drives, as well as a number of ATA drives, now offer 7,200 RPM, whereas the previous generation of hard drives offered 5,400 RPM. Buyers in today's world have the option to choose hard drives that offer 10,000 RPM as well as 15,000 RPM, which offer faster reading and writing of data. However, the faster alternatives can be quite expensive, and they also create considerably more heat and noise, which is why not too many home users think about investing in high speed disk drives.


A hard drive's cache refers to a buffer where it retains data that originates from the drive platter and can be requested by the processing unit. While a number of hard drives continue to use a 2 MB buffer, 8 MB is looked upon as a standard now, and there are various alternatives that come with 16 MB buffers. The size of the cache has a direct bearing on the amount of data it can store. A bigger cache that can hold more data typically helps speed up the data retrieval process.

Buying an Internal Hard Disk Drive on eBay

eBay is home to just about every type of internal hard disk drive you can expect to find. For example, while you have scores of options to choose from in 2.5-inch and 3.5-inch variants, you can also find a number of alternatives in the not so commonly used 1.8-inch and 5.25-inch variants. When it comes to brands, eBay is home to all of the popular ones, which include internal hard disk drives manufactured by IBM, Toshiba, HP, Compaq, Western Digital, and Seagate.

eBay also gives you the option to choose from different interface types, which include ATA, SCSI, SATA, SATA II, and SATA III. In addition, you can also choose between various storage space alternatives, starting from less than 100 GB, and going up in excess of 8 TB.

Buyers who wish to save some money are presented with more than a few options as well, which come in the form of seller refurbished hard drives, manufacturer refurbished hard drives, and used hard drives.


Most new computers come with hard disk drives that not only offer significant storage space, but also come equipped in a manner to enhance a computer's performance, which is among one of the reasons why computers today are much faster than those found a decade or so ago. Using a new hard drive with an old computer that comes with a slow RAM and CPU, as a result, does not really help to exploit its performance-related potential.

Computers that aren't too old, on the other hand, can benefit significantly from a new internal hard disk drive. However, you should make sure that your computer's case provides space to hold an additional hard drive, and you should also establish if your computer comes with the required additional plug to serve as a source of power. When it comes to deciding how much storage space you require, it is best to think ahead and buy a hard drive with more capacity than you currently need, which should definitely be the case if you intend to use your computer for the next year or more.

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