In the old days deciding which hard drive to choose was as simple as looking at the capacity of the drive. Nowadays there are several choices to make like interface types, speeds, storage technologies and physical sizes.

For a simple build one hard drive to hold the operating system and data might be enough but other builds will probably need multiple drives and maybe even RAID configurations.

Let’s have a look at some of these technologies and features to help you buy the best storage drives for your build.

SATA and SSD drives are the most popular choices

These drives are known as mechanical drives because they spin to operate needing more power and are not silent. Even at SATA III their read/write speeds are about 50 – 120 MB/s which is slow compared to the newer SSD drives.

Older computers and laptops use SATA drives for storage and these spin at 7200 rpm and 5400 rpm. The interface that these drives use is called SATA but it should be noted that mechanical drives are commonly referred to as SATA drives as well.

The SATA II interface supports speeds of 3GB/s and the faster SATA III supports speeds of 6GB/s. These speeds are what the SATA interface is capable of not the speeds the drives actually run at.

The newish kid on the block, SSD’s use the same SATA interface but are faster, lighter, use less power and are silent. In fact they can run at read speeds of 500 MB/s and higher, so they blow mechanical drives out of the water!

Solid state drives also use the SATA interface and are the size of laptop drives, 2.5″.

That’s that then, the obvious choice is SSD’s and there is no need for mechanical drives, right? Wrong, the main problem is SSD’s are a not cheap especially for higher capacities, a 1TB is currently $400 whereas a mechanical 1TB drive is about $60 big difference, huh?

I’m guessing most budgets won’t be able to include 1TB SSD’s in their builds.

The good news is that smaller size SSD’s are much more affordable. Using a 120GB or 250GB SSD drive for your operating system and using a high capacity mechanical hard drive for your storage needs is a good comprise. You could also get 2 smaller SSD’s and combine their capacities in a RAID configuration (I will be using this solution and will be showing you how to do this in an upcoming post).

There is another option is a hybrid SATA + SSD drive that aims to give you the best of both worlds by including the SSD drive chips along side a mechanical drive. They are a good choice for everyday builds for ‘normal’ computer use.

What is M.2 and how fast is it?

M.2 is a new interface that has several purposes but the ones we’re interested in are the storage options. M.2 interfaces with the data buses on the computer including the SATA and PCI Express lanes.

The notches on the ends of these M.2 drives indicate what interface they use. One notch on the end tells us it uses the PCIe data lane(s) and 2 notches tells us the drive uses the SATA data lane.

The notches on the ends of these M.2 drives indicate what interface they use. One notch on the end tells us it uses the PCIe data lane(s) and 2 notches tells us the drive uses the SATA data lane.

This means the speed at which M.2 drives perform depend on what the bus can handle. There are currently 2 types of M.2 drives out there at the moment: SATA M.2 drives and PCIe M.2 drives.

The SATA M.2 drives offer a small increase in performance but still are limited by the 6 GB/s SATA III data lane. These are useful for compact builds where space is a problem and there are limited drive bays.

The PCIe M.2 drives offer huge increases in performance like write speeds of 900 MB/s and read speeds of 2200 MB/s. These drives use the M.2 socket on a supported motherboard or are designed to fit into a PCIe slot. These slots need to be PCIe version 3.0 to get the best speeds from these drives.

You should be aware that the data lanes are shared and if you use a M.2 drive one or more SATA or expansion slots will become unavailable.

Physical sizes of internal drives

The standard size of an internal hard drive is 3.5” but the new SSD drives are smaller and are the size of a normal laptop drive of 2.5”.

These drives slot into the drive bays in the computer case and most cases now have bays that accommodate both sizes. If not, you can get a caddie or adapter cheaply that allows you to slot a 2.5” drive into a 3.5” bay.

Although DVD/CD drives are not used as much as before they still come in handy. They have a size of 5.25” in case you’re wondering.

M.2 sockets are multipurpose and so the drives or cards that fit into these sockets vary in length. The code on the drives descriptions tells you it’s dimensions so M.2 2280 is 22mm wide by 80mm long. Be sure to check these dimensions are correct for your motherboard.

How to pick the right drives for you

My recommendation to get the best bang for your buck is to use a combination of SSD and SATA drives. The increase in performance you get with SSD drives is amazing but high capacity drives are really expensive.

A combination of an SSD and one or more mechanical drives is a good way to keep within budget.

A combination of an SSD and one or more mechanical drives is a good way to keep within budget.

Go for a small SSD (maybe 128GB) for your operating system and use one or two SATA drives for storage. You can save money by reusing drives from an old computer or laptop but if you’re buying new mechanical drives, buy the faster SATA III and 7200 rpm drives.

Before buying check the physical sizes of the drives especially if you’re using M.2 drives.

As usual think about what your computer is going to be used for – there’s no point spending lots of money on the fastest SSD drive for an everyday use PC. On the other hand if it’s high end gaming you’re building for, it’s definitely worth the extra expense.

In the next post in this series we’ll be finding out how to pick the right Power Supply for your build.