Choosing the best hard drive

When it comes to permanent storage the only thing going for your computer is a disk drive.

Sunday, 19th July 2015, 10:11 am
JPCT 150713 Alan Stainer. Photo by Derek Martin

It holds the operating system, the programs and the data, so it is pretty important. The question is, which one? There are so many and they pretty much all look good.

To start with, you will need to decide whether you want an HDD or an SSD. An HDD (Hard Disk Drive) is an older technology and is literally a whopping great big magnetic disk that spins around. It is also where the term ‘crash’ comes from due to the (very rare) instances where the read/write head crashes into the spinning disk. An SSD (Solid State Disk) is a different kettle of fish altogether. Using surface mounted wizardry, it is more like a USB flash drive and is blisteringly fast.

The major differences between an HDD and an SSD are thus.

1. HDDs have a much higher capacity pound for pound. To give you an idea, I found a 5 TB (terabyte) HDD for just shy of £170 today. A terabyte is 1000 GB (gigabytes) which is enormous. A similarly priced SSD will give you only 500 GB of storage space. It is possible to buy a 1 TB SSD, but they cost a bit extra.

2. An HDDs speed is measured in RPM. 7200 RPM is a good speed for an HDD. SSDs obviously don’t have an RPM, as there are no moving parts with which to even contemplate a revolution. Instead you may see their read/write rates in terms of MB per second. Regardless of the specific number, an SSD will be much faster than an HDD.

You will also notice this written down next to almost every HDD and SSD you come across, “SATA 6GB/s”. That refers to the speed of the connection, not the speed of the drive itself. HDDs will also have a certain amount of cache. That acts as a buffer between the hard drive and the computer. More is better, so a 64MB cache gives a better performance boost than a 32MB cache.

So the real question you will be asking yourself when you buy a new computer is this, do you need a really large capacity disk drive to store countless photos, music files and whatever else you fancy, or do you need a smaller one that will turn your new computer into the Flash of the computer world?