PC Storage Explained

PC Storage can be categorized into two kinds: Solid State and Mechanical. Mechanical Storage Devices are those hard drives that has a spinning magnetic disk inside that stored data, while Solid State are silicon chips enclosed in a case.

SSD vs HDD

SSD (Solid State Disks) are smaller, silent, faster and expensive storage devices when compared to the larger, spinning, slower and sufficiently cheaper HDD (Hard Disk Drives).

The general advice is to use an SSD as the operating system drive and the HDD for media archiving purposes.

Form Factor

There are different form factors available depending on your selection of SSD or HDD.

• M.2 (M key or M/B key)
• Expansion Card
• 2.5 inch
• 3.5 inch

The choice of Form Factor affects the size it occupies and whether there is compatible connector in your motherboard. But keep in mind that 2.5 inch and 3.5 inch drives are SATA only and can’t use PCI-e bus.

Bus

There are two types of buses

• PCI-e
• SATA

PCI-e is faster than SATA. HDDs always use SATA. PCI-e cards needs to be connected to slots with PCI-e otherwise they will use SATA.

Protocol

There are two protocols for PC Storage

• NVMe
• AHCI

Some M.2 and Expansion Cards uses NVMe while the others use AHCI. SATA based storage use AHCI exclusively.

NVMe is newer and optimised for SSDs. But keep in mind that there are SSDs that cannot use NVMe and only function as AHCI and also there are M.2 slots that can only function in AHCI mode.