2D NAND vs. 3D NAND: What’s the Difference?

2D NAND and 3D NAND are technologies used in desktop and mobile storage. NAND flash memory is used for solid-state drive (SSD) technology to offer more reliable and faster storage in desktop computers and mobile devices. Depending on your goals, you can choose between the two technologies to build servers and backup devices. 

While 2D NAND is now essentially obsolete in modern enterprise storage, understanding the evolution from 2D to 3D NAND helps illustrate why today's 3D NAND technology has become the foundation for all modern flash storage solutions.

3D NAND vs. 2D NAND

3D NAND is now the standard NAND technology, having completely replaced 2D NAND in virtually all new storage products. NAND flash storage technology uses cells stacked within a small chassis to give users a smaller storage component with better performance. 2D NAND devices place storage cells side by side. 3D NAND adds another layer and stacks cells vertically. The current evolution of 3D NAND technology contains hundreds of memory cell layers. By having more memory cells within the drive’s chassis, 3D NAND provides more storage at faster speeds.

How NAND Flash Memory Stores Data

Storage on any device is a series of ones and zeros. The basic storage unit in flash memory technology is called a gate. When electrons are present in the gate, the value is 0. When no electrons are present, the value is 1. Different voltage levels represent different bit patterns—when data is written, precise amounts of electrical charge are injected into each cell. During read operations, the storage controller measures the voltage level and translates it back to bits. The number of voltage levels depends on the cell type: SLC (two levels), MLC (four levels), TLC (eight levels), or QLC (16 levels).

Gates in 2D NAND are aligned horizontally. 2D NAND technology is not as popular now since 3D NAND has better transistor technology to stop the discharge of electrons, which essentially causes data loss. The charge-trap technology in 3D NAND technology is preferred for performance and data integrity.

Understanding SSD Architecture

An SSD combines NAND flash memory with a controller and interface that enables the drive to function as a drop-in replacement for traditional hard disk drives. SSDs include a flash translation layer (FTL), which is internal firmware designed to manage wear leveling, error correction, and bad block management while translating between logical and physical addresses.

A 3D NAND flash storage device also provides dramatically more storage at a lower price than 2D NAND devices. Modern 3D NAND technology reduces power consumption by up to 50% and increases the speed at which the device can write data to cells by three to four times compared to legacy 2D NAND.

Technical Advantages of Modern 3D NAND

Density and Capacity

• 2D NAND: Limited to approximately 128Gb (16GB) per die
• Modern 3D NAND: Up to 2Tb (256GB) per die, with 4Tb dies in development
• Everpure DirectFlash® Modules: Leverage 3D NAND to deliver up to 150TB in a single module (300TB coming soon)

Performance Metrics

• Sequential read speeds: Up to 7GB/s with NVMe interface
• Sequential write speeds: Up to 5GB/s
• Random IOPS: Over 1 million IOPS for 4K random reads
• Latency: Sub-100 microsecond for enterprise 3D TLC NAND

Endurance and Reliability

• 3D TLC NAND: 3,000-5,000 P/E cycles
• 3D QLC NAND: 500-1,000 P/E cycles
• Enhanced error correction with low-density parity-check (LDPC) codes
• Better data retention through improved cell isolation

Benefits of 3D NAND vs. 2D NAND

Because a 3D NAND flash device contains several more storage cells than a 2D NAND device, users get more storage capacity with the newer technology. SSDs have a limited lifespan, especially when they’re used in devices where several writes are performed. For every write, an SSD loses a bit of its lifespan. All SSDs have a limited lifespan, but the additional cells provide more write cycles with a 3D NAND device compared to a 2D NAND device.

Because of the better transistor technology and stacking of memory cells, 3D NAND is the preferred technology for most data centers and organizations. 3D NAND offers faster speeds and additional storage capacity. The downside is that 3D NAND technology is more costly to produce, which makes it more expensive for organizations.

For servers with smaller chassis, 3D NAND devices are preferred because they’re smaller. Server manufacturers have limited space to install hardware, and 3D NAND allows them to provide more storage for their users at a lower cost and without the 2D NAND space requirements. 3D NAND also uses less power, so it causes less drain on an uninterrupted power supply (UPS) battery.

When to Use 3D NAND

Using 3D NAND will lower costs and power consumption. It also has a longer lifespan and offers faster speeds. For most applications, 3D NAND is the clear winner. Newer servers might come with a 3D NAND storage device, but you can also buy them to install additional storage capacity in an existing server. If you’re looking for a new SSD, a 3D NAND device will be cheaper per gigabyte of storage and provide you with terabytes of storage capacity.

3D NAND offers much more storage capacity than 2D NAND. 2D NAND memory blocks store up to 1.6TB, but 3D NAND memory wafers offer up to 128TB. Even with the cost difference, 3D NAND is more beneficial for organizations with large data storage requirements. Data centers and enterprise organizations prefer 3D NAND for its higher storage capacity and data integrity.

Enterprise Use Cases for Modern 3D NAND

High-performance Computing

• AI/ML training data sets requiring massive capacity and high throughput 
• Real-time analytics processing petabytes of data 
• High-frequency trading systems needing consistent low latency

Virtualization and Cloud

• Virtual desktop infrastructure (VDI) supporting thousands of users 
• Container orchestration platforms with persistent storage needs 
• Multi-tenant cloud environments requiring predictable performance

Mission-critical Applications

• Enterprise databases (Oracle, SQL Server, SAP HANA) 
• Electronic health records and medical imaging 
• Financial transaction processing systems

When to Use 2D NAND over 3D NAND

Older devices that have 2D NAND technology can be upgraded to the latest 3D NAND technology. A good way to recycle older 2D NAND technology is to move the 2D NAND device to archive non-critical storage. The archive storage would still have a limited lifespan and need eventual replacement, but using it for simple archives would reduce writes to the number of times files are stored permanently until they’re needed for retrieval.

Conclusion

When shopping for more storage space, you can choose between 2D and 3D NAND technology. In most cases, 3D NAND is the best option for your applications, even if you’re installing storage for personal use. You may even want to replace older 2D NAND technology with newer 3D NAND so that you can take advantage of its lower power consumption and faster speeds.