What’s the difference between SSDs and HDDs? Solid state drives and hard disk drives are similar in their physical specifications, but they store data💟 very differently. There are advantages and disadvantages to each type of drive, and deciding on which type is right for you comes down to how you use your computer. Our guide to HDD vs. SSD shows you how each type of storage drive works and what it means for you.
What is a HDD?
The technology behind hard disk drives🔴 is well known and well tested. Hard disk drives have been around for more than 50 years, steadily increasing their storage capacity and decreasing their physical size. HDDs rely on spinning disks, or platters, to read and write data.
How hard disk drives (HDD) work
Reading and writing
The time it takes for the platter to spin and the actuator arm to find the correct track and sector is known as latency.
The drawbacks to HDDs are a result of the mechanical parts used to read and write data, as physically finding and retrieving data takes more time than electronically finding and retrieving data. The mechanical parts can skip or even fail if they are handled roughly or dropped. This is a concern in laptops, but not as much in desktops. HDDs are also heavier and use more energy than comparable SSDs.
Benefits of a HDD
The benefits of a hard disk drivs are that they are a proven technology, and are frequently less expensive than a solid state drives for the same amount of storage. Currently, HDDs are also available with more storage space than SSDs.
What is an SSD?
How solid state drives (SDDs) work
Reading and writing
When the drive is idle, a process called garbage collection💙 goes through and makes sure the information in the old block is erased and that the block is free to be written to again.
There is another process called TRIM🦩 that informs the SSD that it can skip rewriting certain data when it erases blocks. Because there are a finite number of times any block can be rewritten, this is an important process that prevents premature wear on the storage drive.To further prevent wear on the drive, there is an algorithm to make sure that each block in the drive gets an equal amount of read/write processes. This process is called wear leveling and happens automatically as the drive is working. Because the read/write process requires data movement, SSDs are usually overprovisioned with storage; there is always a certain amount of the drive that is not reported to the operating system, and not accessible to the user. This allows room for the drive to move and delete items without affecting the overall storage capacity.
Benefits of an SSD
One of the biggest benefits of an SSD is how much faster they are than HDDs. For example, the Crucial P5 is our fastest NVMe SSD, delivering impressive read/write speeds up to 3400/3000MB/s. Even portable SSDs are faster than HDDs. With read speeds up to 1050MB/s1 and capacities up to 2TB, the X8 is up to 100x faster than USB flash drives2 and up to 7.5x faster than traditional hard drives2.
Is an SSD a hard drive?
Put simply, an SSD isn’t the same as a hard drive. Hard drives use magnetically sensitive platters which are moved by a motor, whereas an SSD uses flash memory without any moving parts, meaning they are faster.
|Cost||Speed||Durability||Highest capacity||Energy efficiency|
|HDD||Cheaper||Slower||Less durable||10 TB||Use more energy|
|SSD||More expensive||Faster||More durable||4 TB||Use less energy|
- Sequential read speed of 1050MB/s specific to Crucial’s portable X8 drive.
- MB/s speed measured as maximum sequential performance of device as measured by Crucial on a high-performance desktop computer with Crystal Disk Mark (version 6.0.2 for x64). Your performance may vary. Comparative speed claims measured as maximum sequential performance of similarly situated portable SSDs, mainstream portable HDDs and mainstream USB flash drives from vertically-integrated manufacturers selling under their own brands as of June 2019.