SSD Meaning & Definition

Solid-state drives (SSD) are a new generation of storage devices aimed at replacing traditional mechanical hard-disk drives (HDD). SSDs use flash-based memory rather than spinning disks, making them faster, more reliable and more energy-efficient.

This storage technology was previously reserved for enterprise organizations and the most high-end PCs. Technology improvements have made them more affordable so they are now more common in mainstream devices. They are on average more expensive than HDDs but they provide more value. SSDs are available with storage capacities ranging from 32GB up to 8TB.


HDDs consist of an actuator arm that moves across a spinning magnetic disc to read and write data. SSDs use chips called NAND flash memory that hav no moving parts. This means they don’t experience the same mechanical failures as HDDs.

HDDs take longer to boot as the disk needs to ramp up to speed and takes longer to find the information requested. NAND memory chips boot instantly and the SSD can locate information in a fraction of the time required by HDDs. SSD’s far superior read/write speeds are the biggest differentiator over hardware-based storage.

SSDs are also smaller and lighter than mechanical disks, clearing up space for other hardware and allowing for the development of smaller, more mobile devices. They also increase battery life as they consume less energy than HDDs. Overall, SSDs outperform HDDs in how quickly they boot, transfer files, and launch and run applications.

Types of SSDs

SSDs come in a variety of sizes and form factors to serve different needs. They can be external with a standalone enclosure and connect to devices via USB or Thunderbolt cables, but are more commonly internal and connect directly to the motherboard. Internal SSDs are more complicated and leverage multiple types of connections and form factors.

PCIe and NVMe: The Peripheral Component Interconnect Express (PCIe) form factor bypasses SATA connections and plugs directly into the motherboard. They offer high bandwidth and low latency to provide the fastest read and write speeds. These types of SSDs use the Non-Volatile Memory Express (NVMe) interface specification designed to maximize the number of requests sent to SSDs and allow them to simultaneously receive requests from multiple processors. This ultimately leads to higher input/output (I/O) per second. The maximum theoretical sequential read speed for the latest PCIe SSDs is estimated to be 31,500Mbps.

SATA III: HDDs typically use legacy Serial Advanced Technology Attachment (SATA) connections. They’re not as fast as PCIe but many SSDs still use these connections so they can be integrated with older hardware. SSDs that connect via SATA III, the most efficient SATA type, are still much faster and more reliable than HDDs but their sequential read speeds max out at around 600Mbps.

M.2: M.2 is a more versatile form factor that is commonly used in laptops and all-in-one PCs due to their small physical size. Even though they’re smaller, they still offer comparable storage space and performance. They are the more versatile option as they are available in both SATA and PCIe variants.

SAS: Serial-Attached SCSI (SAS) SSDs are a less common form factor that is primarily used in enterprise servers. They deliver faster data transfer rates than SATA connections, making them a better option for server virtualization and high-performance cloud computing.

Common applications

SSDs are growing in popularity in consumer devices like laptops but are strongly preferred for certain applications.

  • Businesses: Many organizations need to store and regularly access massive amounts of data. SSDs allow organizations to access and transfer data quickly, reduce downtime thanks to their reliability, and save on energy costs.
  • Media Creation: Media creators, such as video editors, photographers and music producers often use robust applications for their work. These applications typically read and write from large raw media files which can be a hefty task for HDDs. SSDs greatly speed up the editing and rendering of media.
  • Gaming: Modern games are designed to constantly load and write files to render textures, maps, levels and other game elements. SSDs allow this to happen seamlessly, providing a better gaming experience.


Kyle Guercio
Kyle Guercio has worked in content creation for six years contributing blog posts, featured news articles, press releases, white papers and more for a wide variety of subjects in the technology space.

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