How to Install a Hard Drive

Guide: How to Install a new Hard Drive

This article was originally posted by Techradar in association with, and has been edited by a member of the forum, ‘Fov’.

Adding, upgrading or installing a new hard drive is always about one thing – storage, storage, storage.

For less than £30 you could add a new hard drive to your desktop PC or laptop, not only increasing storage space but also improving performance.

That last bit might sound odd, but adding a new larger drive increases system performance – newer drives store more data in the same space. That increases data throughput, or more simply: stuff loads and saves faster.

How to buy the best new hard drive upgrade
Adding a new drive is simplicity itself on a desktop PC. It’s a case of locating a free drive bay, along with a free data connection and power connection. Once you have those just add the new drive, plug in the two cables and you’re done. But so you know exactly what to look for we’ve put together this simple step-by-step guide.

As you’ll see, physically connecting the hard drive is just half the job. Making sure Windows can read the drive is the last step.

If you’re adding a new drive to be be just used for storage, this job is easy. If you want to replace your Windows boot drive then the job is more complex but really just involves an extra piece of software.

1. Which hard drive do you need?

There are two main sizes of computer hard drive: 3.5-inch and the 2.5-inch. The larger 3.5-inch units are used in desktop PCs and are often called desktop drives. The smaller 2.5-inch are used in laptops. There is a smaller 1.8-inch drives used in mobile devices, such as tablets.

2. Hard drive connectors

For home use there are two main interfaces. Confusingly the first has two names; IDE (Integrated Drive Electronics) or PATA (Parallel Advanced Technology Attachment) is the older connection.
It is the kind you would expect to see with a long rectangle with lots of pins in and is connected via a 55mm wide ribbon cable. These ribbon cables can usually connect two IDE drives at once (and some computers have multiple channels though the second channel is usually used for the optical drives).
The second interface is the newer interface and is called SATA (Serial Advanced Technology Attachment).
Sata being the newer technology gives a much faster interface, larger capacity and gives neater cables. IDE on the other hand is becoming a lot less common and should be avoided if possible.
Again there are further variations which are not common in home use. These are SCSI (Small Computer System Interface) which is an older interface and SAS (Serial attached SCSI – pronounces Scuzzy) which is a newer interface which is physically the same connector as SATA but SAS can not be plugged into a SATA backplane.

A hard drive also needs power. The old-style four-pin Molex connection is being phased out, replaced by the newer SATA power connector pictured below. You may find your PC only offers Molex power connections, if so adaptors are available so you can still power newer devices. You may also find your hard drive has both types, if it does, only use one or the other, not both.

Other points when choosing your new HDD:
Spindle speed:
This is how many times per minute the internal platters inside the drive rotate. The common speed for 3.5” drives is 7.2k RPM. For laptops there are 3 common options; 4.2k, 5.4k and 7.2k.
There are other options such 10k and 15k but again they tend to be either specialised or not for home use.
Spindle speed is very important for a fast hard drive. The faster the drive spins the more data is passed under the drive head. Its always a compromise though. The faster the spindle, the more heat and energy is needed. This is very important in laptops!

The buffer is temporary memory. The bus can move data a lot faster than a hard drive can read or write it so buffer is used to hold data ready to be read or written. Buffer really makes a difference when in normal use due to the reduced time needed to seek the data.
The larger the buffer the faster the drive.

Yet more things to consider!
Im about to go into some more technical details here. Most of which you really dont need to consider. But if you have a yearning for learning you might want to.

Platters are the disks inside the drive which spin. A typical 3.5” drive can hold 5 Platters.
More platters inside a hard drive results in a higher storage capacity, because the total capacity is calculated by multiplying the per-platter capacity with the number of platters. For example, the WD Eco green 2TB drives have a data density of 667 GB per platter. However, more platters also mean more heads, which further increases the risk of hardware failure due to the more moving parts. Friction (and so heat) and energy requirements increase as well (hence the eco green using 3 platters to reduce the power needed).
Access Time
Access time is the count, usually in milliseconds, which it takes the drive to move the head ready to make an operation. It is constituted by the rotational latency (how much time it takes to spin the platter round to the correct place) and the seek time (the time move the arm to the correct place).
The lower the access time the faster the drive.

3. The connectors

Before opening your PC always power it down and disconnect it from the mains power supply and take anti-static precautions. If you open your PC and peer inside you’ll need to locate the bank of SATA connectors, similar to that pictured here. You may also see one or two wide PATA connectors, which you should be ignoring as they’re really only there for slower optical drives.

The Connectors

4. Installing a desktop drive

Once you know which type of drive you can install inside your PC and how it connects, you can buy safe in the knowledge you can connect the drive. The new drive still needs to be physically mounted into a 3.5-inch drive bay. This will usually require four standard case screws. With many cases you slide the drive into place and screw it in, other cases offer ‘quick-release’ systems but again these usually require sliders or a caddy screwing to the drive before physically installing it. It is possible to mount drives into the larger 5.25-inch bay but you will need to buy an additional bay adaptor.

Desktop Drive

5. Connecting the cables

With the drive securely mounted, you can connect the SATA data cable between the hard drive and the motherboard. As mentioned your PC’s power supply may not offer any additional SATA power connectors, in this case you will need a suitable Molex to SATA adaptor. At this point you can start Windows again. If Windows doesn’t start it’s worth checking you haven’t knocked any cables out. If there are still problems, some systems don’t like the order the SATA cables are connected, so it’s worth swapping these around. Otherwise, you many have to use the BIOS to adjust the boot priority of the drives.


6. Partitioning in Windows

Once into Windows, you need to create a storage space on the drive before you can store files onto it. This storage space is called a partition. Open the Start menu, right-click the My Computer entry, select Manage and Disk Management. This lists each physical hard drive in turn and each partition created on it. Windows treats each partition as a separate drive – it’s perfectly possible to create multiple partitions on a single hard drive.

Right click the new drive and choose Initialize Disk, often you will have already been prompted to do this. Windows now knows this is a basic hard drive. To create a partition right click with the mouse over the Unallocated drive and choose New Simple Volume… A dialog will appear asking various questions. You can keep all the default settings, unless you want to split the drive into smaller partitions. In this case choose a suitable size in MB after clicking Next – remember 1,000MB is 1GB. After this process your drive is ready for use.

7. Drive imagingA more complex approach is if you want to replace your old hard drive with the new one, this could be for performance reasons or reliability issues – perhaps you’re going to use the old drive elsewhere for whatever reason. You could install Windows from scratch on the new drive but it is possible to duplicate the old Windows drive on the new one using drive cloning software such as the paid-forAcronis True Imageor the free DriveImage XML. You will need to do all of the steps above and then follow the imaging software’s instructions, but effectively with both drives connected you want to copy the original Windows partition to the new drive. This process can take a while. Once done power done the PC, disconnect the old drive and hopefully you’ll reboot using the fresh-new drive.

Final thoughts
In this guide we have looked at the basics of upgrading your laptop or desktop hard drive. We have not gone into full details of every little variable and like most things in life there is always a compromise to be made to find exactly the right drive for your situation.
We have not looked at some of the exciting features manufacturers are putting into some drives such as detecting drops (great for laptops!) and adaptive fly height (which adapts to errors on the drive and tries to read the problematic section).
Also we have not covered the latest technology which is solid state drives. These do not feature platters which spin but instead store data on non moving parts. These drives are a lot faster but currently offer much lower capacity and higher cost.
Lastly, and most importantly, dont forget to maintain a backup of all your important data!

    About Alex Wall

    "All this wine nonsense! You get all these wine people, don't you? Wine this, wine that. Let's have a bit of red, let's have a bit of white. Ooh, that's a snazzy bouquet. Oh, this smells of, I don't know, basil. Sometimes you just want to say, sod all this wine, just give me a pint of...mineral water." - Alan Partridge

    4 thoughts on “Guide: How to Install a new Hard Drive

    1. I purchased the Toshiba 1T/6G HDD/SSD Hybrid drive Jan 2015, and had it fitted at my local Laptop shop as swopping a drive on a Dell Inspiron N5510 (see YouTube) is a little difficult. The HD is mounted under the Main PCB so keyboard / screen / PCB all have to come out.
      On my Machine the Dell Uti. “PC-Doctor” now crashes when it checks out “Funnel Seek Test” and “Spindle Test” so I can now longer check the dell site for software updates.

      Also from time to time my laptop just sits there, after logging in, for about 10 minutes
      I have done a Check disk which I am now repeating. Toshiba cant help. They have no test utilities, They say “it is up to dell to research the compatibility of after market upgrades with their products?” ( I don’t think so). Well there you go! I wonder if the Seagate Hybrid drive has the same issues?

    2. If adding an SSD drive, a major reason for this is to get faster boot times and loading of programs. Instructions for migrating the OS to the new drive are what would be most useful, ideally for both windows and linux.

    3. 1024KB=1GB Come on guys…

      I would second the call for a documented “live migration” of existing OS install from a HDD to SSD, including things you need to change (BIOS and / or OS) to cater for the difference in drive types (thing like swapping etc).

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