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A solid-state drive (SSD) is a data storage device that stores and retrieves information electronically, usually in nonvolatile NAND flash memory. It has no spinning platters and no moving read/write mechanism. A controller inside the drive decides where data is written and handles the maintenance that flash memory requires. Micron Technology’s glossary defines it this way: “A solid-state drive is a high-performance data storage device that uses NAND flash memory to store and retrieve digital data electronically.”
What an SSD does in a computer
An SSD is storage, not working memory. Files, the operating system and installed programs stay on it when the computer is switched off. Programs that are running at a given moment use RAM, which is volatile and loses its contents when power is removed. In practical terms, the SSD keeps your data, and RAM holds whatever is actively being used.
How an SSD works
NAND flash cells represent binary data. Micron’s overview describes them as organized into pages and blocks. Reads and writes happen electronically, and erasing is performed at the block level. Because the drive has no moving parts, a request to read or write data does not require a physical arm to move over a disk.
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The SSD controller is the part that makes the flash usable. It tracks where each piece of information sits and coordinates access to the memory. Three of its jobs matter most to a general reader:
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- Get NVMe solid state performance with up to 1050MB/s read and 1000MB/s write speeds in a portable, high-capacity drive(1) (Based on internal testing; performance may be lower depending on host device & other factors. 1MB=1,000,000 bytes.)
- Up to 3-meter drop protection and IP65 water and dust resistance mean this tough drive can take a beating(3) (Previously rated for 2-meter drop protection and IP55 rating. Now qualified for the higher, stated specs.)
- Use the handy carabiner loop to secure it to your belt loop or backpack for extra peace of mind.
- Help keep private content private with the included password protection featuring 256‐bit AES hardware encryption.(3)
- Easily manage files and automatically free up space with the SanDisk Memory Zone app.(5). Non-Operating Temperature -20°C to 85°C
Wear leveling
Flash cells tolerate a limited number of write and erase cycles. Firmware spreads writes across blocks so that no single block is worn out much faster than the others.
Error detection and correction
The controller checks stored data for errors and corrects them where it can, so the information read back matches what was written.
Rank #2
- Solid state performance with up to 800MB/s read speeds in a portable drive. (Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes.)
- Back up your content and memories on a storage solution that fits seamlessly into your mobile lifestyle.
- Take it with you on your adventures—up to two-meter drop protection means this durable drive can take a beating. (Based on internal testing.)
- Secure it to your belt loop or backpack for extra peace of mind thanks to the tough rubber hook.
- From Sandisk, a brand professional photographers trust to take on assignments.
Garbage collection
Flash memory cannot simply overwrite a block in place. When a block holds outdated data mixed with current data, the controller copies the valid data elsewhere and erases the block so it can be reused.
NAND cell designs differ between manufacturers and generations. The definition of an SSD does not depend on those details, so this article does not go further into cell-level engineering.
Rank #3
- Upgrade your laptop or desktop computer and feel the difference with super-fast OS boot times and application loads
- Exceptional performance offering up to 535MB/s seq. Read and 500MB/s seq. Write speeds
- Superior performance as compared to traditional hard drives (HDD)
- Ultra-low power consumption
- Backwards compatible with SATA II 3GB/sec
SSD versus HDD
A hard disk drive (HDD) stores data magnetically on platters that spin, with read/write heads that move across them. An SSD stores data in flash memory and has no moving storage mechanism. The table below summarizes the practical differences as described in vendor technical documentation.
| Characteristic | SSD | HDD |
|---|---|---|
| Storage medium | NAND flash memory | Magnetic platters |
| Moving parts | None in the storage path | Spinning platters and moving read/write heads |
| Access latency | Generally lower, because no mechanical seek is needed | Higher, because heads must move to the correct track |
| Operating noise | Silent in normal operation, since nothing spins | Audible spinning and head movement |
| Mechanical shock | No spinning mechanism to disrupt | Spinning and moving parts are vulnerable to mechanical shock |
These are general design differences, not guarantees. An SSD can still fail or be damaged, and the sources do not establish a universal speed ratio or failure rate between the two types. Real-world performance depends on the specific model, the workload, the interface and the host computer. Claims such as “SSDs are 100 times faster” or “SSDs never fail” are not supported by the available vendor documentation.
Rank #4
- Capacity Display Variance: 500GB external ssd often appears as around 465GB on Windows. MacOS can show full 500 GB capacity. This is binary calculation difference and doesn’t affect SSD hard drive actual physical storage
- 1050 MB/s Speed: Instantly access to your files with blazing-fast 10Gbps external SSD read up to 1050MB/s and write up to 1000MB/s. LED Light indicates USB SSD instant activity
- Data Security: Solid state drives S.M.A.R.T. health diagnostics and adaptive TRIM optimizing data block management ensures consistent write speeds and extends the longevity of the portable SSD
- USB-C & USB-A Cable: Both cables featuring rapid USB 3.2 Gen2, this USB SSD effortlessly bridges devices, enabling seamless cross-platform file transfers and backup between computers, smartphones, tablets and iPhone
- Always Fast: No slowdowns for large file transfers. With SLC caching (25% of current available capacity allocated as high-speed cache), this external SSD delivers steady 10Gbps for transfers within the cache capacity
SATA, NVMe and form factors
The word “SSD” describes how data is stored, not which connector or shape a drive uses. Three terms are worth knowing:
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| Term | What it means | Notes |
|---|---|---|
| SATA | A host interface used by many SSDs | SATA SSDs use this interface. Micron notes that NVMe was developed to avoid older, slower interfaces such as SATA. |
| NVMe | A protocol designed for flash-based SSDs | Commonly paired with PCIe. A drive’s advertised speed depends on the PCIe connection the host provides. |
| Form factor | The physical size and shape of the drive | Form factors vary. A drive must physically fit the computer’s bay or slot. |
A drive is interchangeable only when the target computer supports its physical format and its interface. Kingston’s flash-memory technical guide also notes that a host controller can cap transfer speeds, so a faster drive will not exceed the limits of an older or restricted host.
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- MADE FOR THE MAKERS: Create; Explore; Store; The T7 Portable SSD delivers fast speeds and durable features to back up any endeavor; Build your video editing empire, file your photographs or back up your blogs all in an instant
- SHARE IDEAS IN A FLASH: Don’t waste a second waiting and spend more time doing; The T7 is embedded with PCIe NVMe technology that brings fast read and write speeds up to 1,050/1,000 MB/s¹, making it almost twice as fast as the T5
- ALWAYS MAKE THE SAVE: Compact design with massive capacity; With capacities up to 4TB, save exactly what you need to your drive – from large working files to game data and everything in between
- ADAPTS TO EVERY NEED: Whether using a PC or mobile phone, count on the T7 for extensive compatibility²; It’s a true team player when it comes to heavy-duty application usage or file-saving
- HI RESOLUTION VIDEO RECORDING: Record Ultra High Resolution (4K 60fs) videos directly onto the T7 Portable SSD with your favorite camera or mobile devices; Supports iPhone 15 Pro Res 4K at 60fps video and more³
Endurance and lifespan
NAND flash has finite write and erase endurance. Wear leveling and garbage collection manage how that endurance is used, but they do not remove the limit. No single lifespan in years applies to every SSD. The sources available for this article do not support a fixed duration, so a drive’s expected life depends on the model and on how much data is written to it.
When comparing drives for longevity, look at:
- The endurance rating the manufacturer publishes for that exact model.
- The warranty terms, including any limits on total data written.
- How much you write per day, for example heavy video editing versus occasional document storage.
Checking compatibility before buying
If you are moving from a definition to choosing a drive, work through these steps in order. Compatibility comes first, because a drive that does not fit or connect will not work no matter how well it performs on paper.
- Check your computer’s manual or the manufacturer’s specifications for the supported drive type, physical size and interface.
- Confirm whether the system accepts SATA, NVMe over PCIe, or both.
- Confirm the physical form factor will fit the bay or slot available.
- Compare capacity needs with the drive’s published specifications.
- Compare the published endurance rating and warranty against your expected workload.
No specific make or model is recommended here, because the right drive depends on the target system and on current pricing and availability, which this article does not cover.
Origins of the technology
Micron’s glossary states that a 20 MB flash-based SSD was built for IBM laptops in the 1990s and that Micron launched its RealSSD product line in 2007. These dates come from a manufacturer’s glossary rather than an independent history of the technology. They are useful background but are not needed to understand what an SSD is today.
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