Computer Parts | Hard Disk Drive

The Hard Disk Drive stores all your information such as your operating system, games and documents, which are saved It could be a non-volatile storage, which suggests that the contents of the HDD isn’t lost if the PC is converted. New HDD’s are not as expensive as you would think for such an important part of your new or refurbished computer build and you can even move your current hard drive contents lock, stock and barrel if you need a really easy upgrade.

Hard Disk Drive

A hard disk drive

There are 3 different sorts of traditional hard disk drive, which are IDE/ATA, SCSI, SATA (Serial ATA). If you buy a new computer from a retailer then you are more likely to have a SATA hard drive installed inside, but this has only become normal over the last five or six years so IDE connections are still being used extensively. SCSI is principally used for servers and powerful workstations as they provide better knowledge transfer rate that leads to higher performance IDE drives so it is unlikely that you sill find them in a consumer desktop computer system.

Recently Solid State Drive (SSD) have gained popularity due their high performance, size, energy potency and no moving components. They offer a top performance and is ideal if you would like to make a silent pc as the lack of moving parts make it almost silent. SSD drives are still quite expensive compared to traditional drives and the capacities are not as large.

You can obtain a reasonable sized HDD for a competitive price. My recommendations are shown below.

A Quick Tangent: RAM (or DRAM)

Before we get onto the important hard disk drives, we should have a very quick cap on the difference between hard drives and RAM. Most computer retailers and consumer tech writers refer to the memory modules in your computer as random-access memory and to an extent they are correct but in a bit of a misnomer which I briefly discuss on my page about buying RAM.

A DDR RAM Module

These are sticks of RAM – these may hold information while you are working with your computer, but they are not hard disk drives and wipe clean every time you power down.

The memory modules that we accept as RAM though retrieve information from the hard disk drives that are needed by the computer there and then and store them for rapid access. Memory modules in your computer or laptop are much faster at reading and writing than your hard disk drive and that is why RAM is important for your computer.

The big difference between your DRAM memory modules and your hard drive is that when you shut down your computer every night; the memory modules wipe themselves clean whereas your hard drive retains the memory.

Another Quick Tangent: USB Thumb Drives

Something that confuses consumers is the difference between types of flash memory for computers. From here on in we are going to remove the confusion; we have Flash Storage which is the memory on the SD Memory Card you have plugged into your mobile phone or camera, and SSD Storage which is your hard disk drive technology. Typically you will find that flash storage drives are much lower quality than SSD.

Back to Hard Drives…..

SSD Technology

Solid-State Drives do not have the moving parts of the spinning disc and the needle which you will find on a traditional IDE or SATA hard drive. The information is stored in NAND flash memory chips; how it is done would take up far more space than we have here to talk about it. The type of flash memory in a SSD differs from that in a DRAM memory module in that it is non-volatile; that means that when the power is removed from a SSD hard drive then the data remains stored.

The Major Differences

So far we have talked a lot about the different technology but we want to help you decide on what you need as a new hard disk drive for your new or refurbished computer. The most obvious thing that we should tell you is that both traditional and solid state hard disk drives will store your data, let you boot Windows/Linux/Other and will let you play your games/research/do homework.

How HDD and SSD Actually Works

The fundamental difference that is making SSD gain popularity is how versatile it can be without any moving parts.

A traditional hard drive is formed of a number of discs which spin and are read by a needle in a similar way to the vinyl records of the 33, 45 and 78RPM eras. This means that while the hard disc drive is being read at up to 10,000 RPM, the slightest tremor could mean that the needle damages the disc or jumps off the plates altogether and rendering the drive inoperable.

A solid-state drive relies on electrical pathways to store and retreive information instead. The information is stored on groups of memory chips and not needing to use  a needle to retreive them. This makes the SSD drive perfect for environments where the computer it is installed in moves or vibrates; such as a laptop on an express train or a tablet computer being used on the shop floor.


IDE and SATA Hard Disk Drive

Ignoring the dust (these are drives I actually use) the top drive is an older IDE Hard Drive; the bottom is a newer SATA hard drive.

If you are building a completely new computer then all consumer motherboards should come with SATA built into the motherboard so it is just plug and play …. or plug and configure. If your computer retailer can not tell you that there is SATA on board then simply walk away.

If you are partly upgrading a old computer then things do get more complicated and you might find that you need an IDE hard drive. Here is a simple way to tell what hard drives look like between the two. Lets look at the image on the left:

  • The top HDD is an older IDE hard drive – You can tell this because there are two very different sections to the power and data supply; the four large pins on the right hand side are the power supply and you will find a large moulded plug on your power supply leads that will plug into this. The long row of pins on the left hand side of the drive are for the data, this will run from your hard drive to the motherboard using a ribbon cable.
  • The bottom HDD is a newer SATA drive – It may not be obvious at first but the two connections for power and data are on the bottom left edge of the drive in this image. The longer inverted L shape is the connection to the power supply and the shorter L shape connection is for the data connection to the motherboard.

Many motherboards still offer both types of connection, but for both cost and future proofing, I always suggest you use SATA technology whenever you upgrade; SATA is now almost always cheaper.

Hard Drive Capacity

The most important thing to say first is that if you store all of your information on a single hard disc drive (usually called C:/) then you must make sure you know how much storage you need. SSD storage drives are inherently expensive to buy per GB of storage compared to the traditional alternative, as well as the physical storage size being much less.

Traditional storage drives can be massive in terms of what your average computer already has installed.  A quick search of popular online retailers show that you can pick up a branded Seagate 4TB HDD for less than £150 which for the same price you would be expecting something like a Samsung 250GB SSD which is just a fraction of the size. Size is not an issue if you are simply using the computer for keeping a set of accounts spreadsheets, writing a few letters and the occasional photograph; but if you are storing a lot of video clips, storing your BBC iPlayer downloads or installing modern games then you need to make sure you have enough.

The size of SSD capacity is limited to what is commercially available on the market. On the consumer market for SSD drives, it is unusual to see a drive that is larger than 512GB whereas traditional drives are found with up to 4TB as we saw above.

My Recommendations for Hard Disk Drives

If you are building a new computer from scratch then you should be looking at:

Western Digital Traditional Hard Drives  for big capacitiesamazon-uk-wide-orange

Samsung 840 Solid State Drives for high speed amazon-uk-wide-light


or see About My Computer  to see what I have installed at home.