What is an SSD?

A solid-state drive (SSD) stores the operating system, programs and files even when the computer is off. It uses flash memory rather than the spinning magnetic disks found in a traditional hard disk drive (HDD).

What an SSD changes

An SSD can read many small pieces of data quickly. This often makes starting the computer, opening programs and loading files feel faster than with an HDD. Because it has no spinning disk or moving read head, it is also quiet and less vulnerable to damage from ordinary movement while operating. Any storage device can still fail, so important files need a backup.

SSD, RAM and capacity

The SSD is long-term storage. RAM is temporary working space for active programs. A 1 TB SSD provides room for files; it does not mean the computer has 1 TB of RAM. Likewise, installing more RAM does not create more space for photos or games.

Capacity is usually stated in gigabytes (GB) or terabytes (TB). The space Windows reports may appear lower because drive makers use decimal units and operating systems may use binary units, as well as reserving space for system data.^[1]

SATA and NVMe

SATA is an older storage connection used by many 2.5-inch SSDs. NVMe is a protocol designed for SSDs, usually connected through PCI Express. Many NVMe drives come in the compact M.2 shape, but M.2 describes a physical form factor rather than guaranteeing NVMe support. Check the computer's slot and interface specifications before buying.

For everyday browsing and office work, the change from an HDD to any suitable SSD is usually more noticeable than the difference between two fast SSDs. Large file transfers and specialist workloads can show bigger differences.

Keep a backup

An SSD can stop working without much warning. Keep at least one separate copy of irreplaceable files and check that you can restore it. A backup is especially important before replacing a drive or reinstalling an operating system.