Hard Disk and SSD Drives

Useful information on hard disk and SSD drives

A hard disk drive (HDD)

A hard disk drive (HDD)

If a desktop or laptop PC doesn’t come with an SSD in one of its four main form factors shown at the top of this page – 2-5-inch, M.2, mSATA or PCIe – it  must contains at least one internal hard disk drive (HDD) or SSHD, which is a combination of an HDD and an SSD as the permanent mass storage device for its operating system and software. The image above is of a standard HDD.

The new very thin, relatively expensive and light laptops have an SSD instead of a hard disk drive, which means that due to the higher cost of an SSD drive their data storage capacity is much less than most current standard laptops.

The image below shows a 2TB SSHD. Click on it to view its full size. You can install the operating system and games on the SSD part of the drive and applications and files on the HDD part. This makes the PC work as fast as an SSD.

Seagate 2TB SSHD drive that is a combination of an SSD and a Hard Disk Drive - £85 in Jan. 2019

Seagate 2TB SSHD drive that is a combination of an SSD and a Hard Disk Drive – £85 in Jan. 2019

SSDs have become very much cheaper since 2017

SSDs have become much cheaper since 2017. In January 2019, you could get a 500/1000GB 2.5-inch form factor drive for £60/£120.

SSDs that use an M.2 form-factor slot on the motherboards that provide them are relatively inexpensive. A 500GB/1TB M.2 SSD costs around £65/£120.

However, a 128GB mSATA form-factor SSD (£70 in Jan. 2019) costs about the same as a 500GB M.2 form-factor SSD. mSATA form factor SSDs are the most expensive by far.

Note that an internal 2.5-inch SSD uses the same serial SATA interface as a standard hard disk drive. Also note that, as with external hard disk drives, portable SSDs are available that use the USB interface.

SSD Form Factors: 2.5-inch, mSATA, M.2 –


The M.2 motherboard slot interface mostly used for SSDs

M.2 slot (bottom) on a Gigabyte motherboard

M.2 slot (bottom) on a Gigabyte motherboard. Click on the image to view its full size

Crucial SSD card drive for the M.2 motherboard slot

Crucial SSD card drive for the M.2 motherboard slot – 500GB and 1TB SSD cards are relatively cheap – £60 and £115 in January 2019

Most recent motherboards come with a M.2 (m-dot-2) slot. There is too much to know about this motherboard slot to put it on this page, so a good link is provided below instead. At some point I will write my own page on it. The main use of the slot is to provide an SSD as card that exceeds the speed of an SSD drive using the SATA interface. Wi-Fi cards for the slot are available.

Here is the essential information that you need to bear in mind when purchasing an M.2 SSD.

M.2 SSD Keying

“Currently an M.2 SSD has either one of three key types: B, M or B+M, while a socket can only have one key. As the key positions of B and M are slightly different, the M. SSD can only be installed one way.”

M.2 SSD Length – 2230- 2242 – 2260 – 2280 – 22110 (e.g., 2280 = 22mm wide and 80mm long.)

“As the M.2 standard requires the SSDs (or, other types: WiFi, Bluetooth etc) only have chips on the upward facing side, this means that greater capacity drives are usually longer since they require more storage (NAND) chips. Generally there are up to five lengths of M.2, however not every motherboard or notebook can accommodate them all.”

Buying An M.2 SSD? How To Tell Which Is Which – Provides illustrations of the different keying and lengths –


Can an M.2 SSD overheat and  so require a heatsink?

If the cooling in the PC’s case is adequate, there should not be any need to install a heatsink on an M.2 SSD, because they do not usually overheat even when long file transfers are taking place. However, if for some reason the temperature around the SSD in the case is hot, such as when the graphics card is blowing hot air on to it, if the ambient temperature cannot be lowered and it is responsible for making the drive overheat, a heatsink should fix the problem, as in the case covered by the following video.

That said, I have come across an overheating problem with a specific make and model of M.2 SSD – the Crucial 500 GB MX500 SATA M.2 SSD – 2280 – £70 (Jan. 2019), which is covered in the following post – Problems with M.2 SSD drives – NVMe – key and length compatibility, overheating and faulty hardware encryption.

M.2 SSD installation

The image, below, from the user manual of an Asus motherboard, show how an M.2 SSD is fitted. The screw is removed, the card is inserted in the M.2 slot and is then screwed in. Note that the SSD has to support the M.2 slot. You can’t just buy an SSD and use the slot to install it.

M.2 motheboard slot for SSD and Wi-Fi cards showing an SSD card

M.2 motherboard slot for SSD and Wi-Fi cards showing an SSD card

“There’s a lot to unpack, starting with the fact that there’s more than one kind of M.2 connector, more than one type of interface that can be used with M.2, and more than one kind of M.2 card.” –

Understanding M.2, the interface that will speed up your next SSD –


Corsair Force 60GB Solid State Drive

Corsair Force 60GB Solid State Drive

The mSATA slot on a motherboard is for an mSATA form-factor SSD

mSATA SSD form factor for an mSATA slot on the motherboard

mSATA SSD form factor for an mSATA slot on the motherboard – A 128GB mSATA SSD (£70 in Jan. 2019) costs about the same as a 500GB M.2 SSD.

Page 4: SSDs – Performance, installation and reviews