How Do You Replace Hard Drives In A Computer?

How Do You Replace Hard Drives In A Computer?

Last Updated on by Daniel Lawrence

Avid computer operators might be interested in knowing how to replace the old hard drives with a better and improved version. In this review, we’d be sharing the topic ‘how to replace a hard drive in a computer.’ Read through to gain knowledge.

What Is A Hard Drive?

The hard drive is where a computing device stores data for the long term — not just the things you save, but all the code required for the operating system, the framework browsers use to access the internet, drivers for accessories, and everything else. When referring to computer storage, “hard drive” (or solid-state drive, see below) is typically used.

Every hard drive has a specific amount of space. Some of that space is automatically consumed by the OS and backup installations. However, the rest can be filled with data you download and save, whether it’s a new app or a funny cat picture someone shared.

Hard drive space isn’t as important now as it once was. That’s because cloud-based software doesn’t require local storage. Data can be stored in the cloud as well, freeing up precious space on the hard drive.

What Is the Best Hard Drive Size?

That depends. If you simply need to transfer a limited number of files between a computer and a backup drive, a smaller drive ( Expansion Drive or Backup Plus ) will work. If you want to back up your entire computer or several computers — or if you store a lot of videos and/or audio — you’ll want a larger drive (Backup Plus Desktop Drive). Here is an estimate of how much you can store on a hard drive (up to 10 TB).

How a hard drive works

In your computer’s hard drive, there aren’t really any iron nails. There’s just a large shiny, circular “plate” of magnetic material called a platter, divided into billions of tiny areas. Each one of those areas can be independently magnetized (to store a 1) or demagnetized (to store a 0).

Magnetism is used in computer storage because it goes on to store information even when the power is switched off. If you magnetize a nail, it stays magnetized until you demagnetize it. In much the same way, the computerized information (or data) stored in your PC hard drive or iPod stays there even when you switch the power off.

The platters are the most important parts of a hard drive. As the name suggests, they are disks made from a hard material such as glass, ceramic, or aluminum, which is coated with a thin layer of metal that can be magnetized or demagnetized.

A small hard drive typically has only one platter, but each side of it has a magnetic coating. Bigger drives have a series of platters stacked on a central spindle, with a small gap in between them. The platters rotate at up to 10,000 revolutions per minute (rpm) so the read-write heads can access any part of them.

There are two read-write heads for each platter, one to read the top surface and one to read the bottom, so a hard drive that has five platters (say) would need ten separate read-write heads. The read-write heads are mounted on an electrically controlled arm that moves from the center of the drive to the outer edge and back again. To reduce wear and tear, they don’t actually touch the platter: there’s a layer of fluid or air between the head and the platter surface.

Is Hard Drive Speed Important?

Spin speed (rotations per minute, or RPM) is relatively important. The faster a disk (platter) spins, the faster your computer can find the file you want.

A 7,200 RPM hard drive is obviously faster than a 5,400 RPM hard drive. But with external drives, you’ll hardly notice a difference between the two RPM speeds. The same holds with internal drives, especially with smaller files. However, you’ll see a noticeable improvement on a 7,200 RPM hard drive with larger files and applications.

Two types of drives

A hard drive can be internal or external.

Internal means a hard drive is located inside a computing device and directly connects to the motherboard, but it’s not always upgradable. For instance, a desktop side can be easily removed to disconnect the old drive and connect the new drive. It’s a quick, simple upgrade.

On laptops, however, the upgrade process may not be quite so simple. Typically there is a door along the bottom providing access to the drive. Other laptops, like Apple’s MacBooks, don’t have removable storage. Read the specifications on the manufacturer’s websites on how to change a laptop’s drive properly.

External means a hard drive is located outside the PC and typically connects through a USB or Thunderbolt cable. This option is typically slower due to the connection, but it can also be detached from the parent PC without any major issues.

Besides internal and external, a hard drive can be a hard disk drive (HDD) or a solid-state drive (SSD). There’s a huge difference between the two that we explain in a separate article, SSD versus HDD. However, here are the shorter explanations:

HDD: Hard drive disks use a spinning magnetic disk that holds information inscribed in very tiny tracks — a bit like a record player. This requires moving parts, specifically heads to read and write data to the disk as needed and propulsion to spin the disk. It’s a simple method, making HDDs very inexpensive to purchase, especially when creating extensive storage setups.

SSD: There are no moving parts in SSDs. Instead, these drives use semiconductors that store information by changing the electrical state of very tiny capacitors. They are much faster than HDDs and can store information more easily without the risk of parts wearing out. SSDs are why modern PCs boot up so fast.

How to install a hard drive in your computer

Installing an internal hard drive is one of the more straightforward upgrades out there—and is often a better option than using external drives that may be dropped or misplaced.

The process usually requires no more than mounting it, connecting a couple of cables and formatting the drive for use. Still, there are a few things you should know to make installation as smooth as possible.

Installing a hard drive in your PC doesn’t necessarily follow the same procedure as installing an SSD. If you’ve opted for a solid-state drive, be sure to check out our companion guides explaining how to install an SSD on a desktop and a laptop. SSDs tend to offer much faster speeds than hard drives, but hard drives offer significantly more capacity at lower prices.

  • Drive cages, bays, and mounting options

Internal 3.5-inch hard disk drives are typically mounted in a drive cage or an available drive bay. Placement and orientation of the cages or bays will vary from case to case. The most common location is at the lower front, near the intake fans, and away from other components. Drive cages/bays will most often be mounted perpendicular to the bottom of the chassis, while drives mounted in the cages usually sit parallel to the bottom of the case.

In mainstream cases, drive connectors will typically point to the rear. In enthusiast-class cases, it’s becoming more common to see the drive’s connectors facing the right side, making it easier to route and hide cables behind the motherboard tray. Some enthusiast-class also cases give users the ability to remove drive cages or to mount them in different positions to optimize airflow and simplify cable management.

  • Mounting your hard drive

Physically mounting the hard drive in a PC is probably the most difficult part of the installation process.

Securing the drive to a cage usually requires four screws on the sides or bottom of the drive. Many cases—especially enthusiast cases—use tool-less trays that hold the drives with simple pins and clips.

Using screws is the more robust mounting method, but tool-less trays are fine for systems that won’t be moved around much.

Drives last longer when they stay nice and cool. When mounting drives in a system, try to leave as much space between them as possible to maximize airflow over the tops and bottoms. Positioning the drives directly in front of an intake fan also helps.

  • Connect the hard drives with SATA

Once the drive is mounted, connecting it to your system is quick and easy.

Virtually all new desktop hard drives sold today use the SATA interface (unless you’re dealing with servers). SATA uses simple cables that are keyed to fit on the drive and motherboard connector one way.

Connect one end of the SATA cable to the drive and the other end to an available SATA port on your motherboard, and you’re halfway there.

You may find the SATA cables included with your new drive or motherboard feature different connectors: straight ends or right-angle (L-shaped). Some may have metal retention clips, while others do not. The shape of the connector makes no difference in performance.

I like to use SATA cables with right-angle connectors on the drive side, provided there is adequate clearance between any drives in the system. Using right-angle connectors on the motherboard side will result in blocked ports, because the connector may overlap adjacent ports.

Try to find SATA cables with metal retention clips, because they help keep the connectors secured. Most SATA 3 (6-gigabit)-compliant cables will usually come with the clips.

When you’re done connecting the SATA cable, you’ll have to connect the drive to your power supply unit (PSU). The  SATA power cable from your PSU, like the SATA data cable, is keyed to fit onto the drive one-way. As long as you don’t force it, there’s really no way to mess it up.

  • Prepare the hard drive for use

Once you’ve mounted and connected the drive, power up your system and enter the BIOS/UEFI. You can usually access the BIOS/UEFI by pressing the DEL or F2 keys right after powering up the system. Usually, your system will display a message along the lines of “Press DEL to enter Setup.” Consult your motherboard’s manual for the correct key.

In the BIOS, go to the standard System Settings menu or the Integrated Peripherals > SATA menu to see all of the drives installed in the system. If all of your drive controllers are enabled and the drive is properly connected (and functional), it should be listed in the BIOS.

If the drive isn’t listed, shut down your PC. Double-check all of the connections, boot into the BIOS, and check again. If the drive still isn’t showing up and all the connections are secure, try plugging the SATA data cable into a different port on the motherboard.


Now you can start thinking about adding another hard drive down the road. Many computer users have more than one drive.