Technology
How does an SSD work?
An SSD (solid-state drive) works by storing data as electric charge trapped in billions of tiny flash-memory cells, with no moving parts. A controller chip decides where to write and read, making SSDs far faster and more durable than spinning hard drives.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how an SSD works.
Step by step
- 1Data is held in NAND flash cells that trap electrons to represent 1s and 0s.
- 2The charge stays put even with the power off, so storage is non-volatile.
- 3A controller spreads writes evenly ('wear leveling') so cells don't wear out early.
- 4With no moving parts, access is near-instant and far more shock-resistant than a hard drive.
- 5Cells wear out after many write cycles, but modern drives last many years in normal use.
Frequently asked questions
- Why is an SSD faster than a hard drive?
- It has no spinning platter or moving head to wait on — data is reached electronically almost instantly, so it's many times faster.
- Do SSDs wear out?
- Each flash cell tolerates a limited number of writes, but wear-leveling and large capacities mean typical drives outlast most users' needs.
- Does an SSD lose data when unplugged?
- In normal use it retains data for years without power; only after very long unpowered storage can the charge slowly leak.