SSD (Solid State Drive) is a storage device that uses flash memory chips to store data, with no moving parts. Unlike traditional HDDs that use spinning magnetic platters, SSDs access data electronically, making them significantly faster, more durable, and more energy-efficient. The lesson What Is Storage? explains how storage devices keep your files, applications, and operating system safe even when power is off.
Why it matters
SSDs are the single most impactful upgrade for making a computer feel faster. The lesson Why Some Computers Feel Faster explains how storage speed affects perceived performance. When your CPU needs data from storage, an SSD can deliver it 10-100 times faster than an HDD, dramatically reducing load times for applications, boot times for your operating system, and wait times when opening files.
How SSDs work
SSDs store data in NAND flash memory cells—the same technology used in USB drives, just much faster and with more capacity. Data is stored as electrical charges in memory cells organized into pages and blocks. Because there are no moving parts, SSDs can access any data location almost instantly (low latency), while HDDs must physically move a read head to the right location.
SSD interfaces
SSDs connect to your computer through different interfaces that affect speed:
- SATA: The same connector used by HDDs. Limited to about 550 MB/s. Good upgrade for older computers.
- NVMe over PCIe: Connects directly to the motherboard via PCIe lanes. Speeds of 3,500-7,000+ MB/s. Standard in modern computers.
Trade-offs vs HDD
SSDs cost more per gigabyte than HDDs, so large storage needs (like media libraries or backups) may still favor HDDs. However, for your operating system and frequently-used applications, an SSD's speed advantage is transformative.
See more
- HDD
- PCIe
- RAM
- ROM
- Firmware
- What Is Storage?
- How Programs Load Into Memory
- Why Some Computers Feel Faster