Flash versus SSD storage: What's the difference?

Flash storage refers to the memory technology itself, comprising electronic memory chips that store data without moving parts. SSD (solid-state drive) storage describes a complete storage device that uses flash memory to replace traditional hard disk drives (HDDs).

Below we explore these types of storage technologies in detail.

Flash storage is a type of data storage technology that uses flash memory chips to write and store data. Flash memory is non-volatile, which means it retains data even without power. Flash stores data as electrical charges in memory cells arranged on silicon chips, with no moving parts, which makes it faster and more durable than traditional spinning disk drives.

Flash storage uses two main types of memory: NAND and NOR.

• NAND flash features high storage density, smaller cell size and faster write and erase speeds than NOR. These capabilities make it well suited for high-capacity storage applications.

• NOR flash offers faster read speeds and random-access capabilities than NAND, making it ideal for applications like firmware, BIOS chips and embedded systems. However, NOR flash has slower write and erase speeds, reduced storage density and higher per-bit costs.

NAND has emerged as the dominant storage technology for most applications due to its higher density, faster performance and lower cost.

Flash storage emerged in the 1980s as the need for compact, non-volatile storage grew alongside the rise of more portable devices. In 1986, Toshiba introduced NAND flash for high-capacity storage applications; in 1993, Intel introduced NOR flash, designed for firmware and embedded systems.

Mainstream adoption of flash took off with the introduction of two devices. These devices were the USB flash drives (introduced in 2000) and the Apple’s flash-driven iPods (introduced in 2005). By the end of the 2000s, flash-based SSDs started displacing HDDs in both laptops and data center environments.

Cell technology has evolved significantly over the years, from single-level cell (SLC) to multi-level cell (MLC), then triple-level cell (TLC) and quad-level cell (QLC). In the 2010s, 3D NAND technology substantially increased storage density and lowered costs.

Today, flash storage dominates the consumer and enterprise marketplaces. According to Enterprise Precedence Research, the global enterprise flash storage market reached USD 21.92 billion in 2024. Furthermore, it is projected to grow from USD 23.71 billion in 2025 to approximately USD 48.03 billion by 2034, with a CAGR of 8.16%.¹ The increased adoption of cloud computing and virtualization technologies, along with demand for enhanced data security and compliance influence and drive this growth.

Flash storage extends well beyond SSDs, powering USB flash drives (also called USB thumb drives), memory cards (such as SD cards), smartphones, digital cameras and countless other devices. In enterprise settings, flash storage powers all-flash arrays and supports applications ranging from large-scale data centers to IoT sensors and edge environments.

A solid-state drive (SSD) is a storage device that uses non-volatile solid-state memory, typically NAND flash, to store data without moving parts.

From the early 2000s onward, SSD drives have gained widespread adoption in consumer and enterprise markets, valued for their exceptional performance and rapid data access speeds. Today, SSDs are the primary storage medium for everyday devices like MacBooks, Mac desktops, Windows PCs, laptops and gaming systems.

Unlike HDDs and diskette drives, which use magnetic storage with mechanical components (for example, platters, spinning disks, read/write heads), SSDs use NAND flash memory to store data electronically. This approach eliminates physical delays and delivers faster data access.

For a deeper dive, check out “Hard disk drive (HDD) versus solid-state drive (SSD): What’s the difference?“

The memory chips in SSDs are organized into blocks, which contain cells (sometimes called pages or sectors) that store individual memory bits. SSDs use wear-leveling to evenly distribute writes across cells, extending the drive’s lifespan.

SSDs are available in multiple form factors, which refer to the device’s physical size, configuration and arrangement. The 2.5-inch format is the most common for desktops and laptops, while M.2 drives connect directly to the system board for a more compact design.

According to a study from the Mordor Intelligence research, the SSD market reached USD 61.30 billion in 2025. Furthermore, it is expected to reach USD 129.62 billion by 2030, growing at a 16.16% CAGR.² 

The demand for artificial intelligence (AI) infrastructure, the cloud provider data center expansion, plus the ongoing shift from hard disk drives to solid-state storage solutions, are the elements that drive this growth.

Nonvolatile memory express (NVMe) is a host controller interface and storage protocol that accelerates the transfer of data between solid-state drives (SSD) over a peripheral component interconnect express (PCIe) bus connector.

NVMe helped advance the SSD storage, reaching transfer speeds of up to 20 gigabytes per second (Gbps)—more than three times the speed of older SATA SSDs. Many of today’s high-end NVMe SSDs also include DRAM cache, which optimizes performance.

NVMe SSDs are valuable for applications that require high-speed data access, including virtualization, real-time analytics, AI workloads and content creation. While every NVMe device is an SSD, not all SSDs use NVMe. For example, older SSDs typically use SATA interfaces.

To learn more, check out “SSD versus NVMe: What’s the difference?“

Looking ahead, the demand for flash and SSD storage will continue to evolve to meet the needs of consumers and enterprises, driven primarily by AI- and cloud-generated data.

Here are a few technologies that demonstrate how the market is evolving. 

• 3D NAND

• QLC and PLC NAND

• All-flash-arrays

• Computational storage

Introduced by Samsung in 2014, the 3D NAND has become critical in the age of AI. 3D NAND flash stacks memory cells vertically across multiple layers on silicon wafers, delivering higher data storage density, increased capacity and reduced cost per bit.

With write speeds up to 50% faster than traditional NAND-based SSD solutions, 3D NAND has become crucial for deploying AI applications like generative AI (gen AI) and machine learning (ML). On the consumer front, 3D NAND powers everyday devices that increasingly need more storage, including smart TVs, laptops and SSDs.

Quad-level cell (QLC) and penta-level cell (PLC) NAND technologies are expanding storage capacity alongside triple-level cell (TLC) NAND, providing cost-effective, high-capacity solutions for enterprise data centers.

These higher-density cell technologies store more bits per cell (for example, four for QLC, five for PLC), enabling greater capacity at lower cost.

QLC flash drives increase density by 33% over TLC, making them well suited for read-intensive workloads, such as archival storage, content delivery and data analytics. QLC and PLC have tradeoffs in write performance and lifespan compared to TLC. However, they play a crucial role in supporting apps (for example, media streaming, gaming devices) where capacity and cost efficiency are priorities over sustained write speeds.

All-flash arrays (AFAs) are external storage systems that use flash media, such as SSDs, for persistent data storage.

AFAs have evolved with several key trends shaping their development, including the adoption of NVMe technology, the emergence of software-defined storage (SDS) solutions and the integration of AI for storage management. These advances make all-flash arrays increasingly attractive for enterprises managing large-scale data operations with demanding performance requirements.

Computational storage places processing directly onto storage devices. This process reduces data movement, network congestion and latency, which is valuable for AI and ML workloads that process massive datasets.

By enabling operations like filtering, compression and transformation at the storage layer, computational storage helps enterprises accelerate application performance.

To recap, flash storage and SSDs are closely related but different technologies. Flash refers to the storage medium itself, while SSDs are storage devices that typically use flash memory. Understanding this distinction supports strategic decision-making about storage infrastructure.

At the industry level, the shift from traditional hard disk drives to flash-based storage has transformed enterprise IT, delivering faster performance and greater reliability. As data demands continue to grow, flash and SSD storage will remain crucial to modern computing infrastructure.