As data continues to grow at unprecedented rates - from AI workloads to cloud storage to high-resolution media - storage solutions need to keep pace. KIOXIA’s QLC (Quadruple-Level Cell) flash is designed to meet this demand, storing 4 bits of data per memory cell. By increasing storage density without dramatically increasing cost, QLC flash opens new possibilities for high-capacity devices and read-intensive applications.
Why QLC Matters
In NAND flash, the “level” of each cell determines how many bits it can hold. SLC (Single Level Cell) stores 1 bit, MLC (Multi Level Cell) stores 2, TLC (Triple Level Cell) stores 3, and QLC stores 4. QLC dramatically increases capacity while controlling cost, making it ideal for applications where every terabyte counts.
Kioxia’s Approach to QLC
Based on our 8th generation BiCS FLASH™ 3D flash memory, Kioxia’s latest QLC flash device is designed to push the limits of high-capacity storage. Kioxia currently offers the highest capacity in the industry1, reaching up to 4 TB in a single package thanks to a 16-die stacked design. This is achieved through the innovative CBA (CMOS directly bonded to array) technology, which optimizes CMOS logic wafers and NAND cell wafers separately before bonding them together.
Looking ahead, Kioxia plans to introduce 32-die stacks, reaching 8 TB in a single package. This advancement has generated significant buzz from customers, analysts, and competitors alike.
While the 2 Tb QLC device focuses on capacity, the 1 Tb QLC device is performance-driven, offering roughly 30% faster sequential writes and a 15% improvement in read latency2. This makes it ideal for high-performance applications such as client SSDs and mobile devices.
Key Benefits of KIOXIA’s QLC Flash
- Unmatched Capacity: Industry-leading1 die density enables larger storage devices.
- Cost Efficiency: High-capacity storage at a lower cost per bit.
- Optimized for Read-Intensive Workloads: Ideal for applications that read frequently.
- Advanced CBA Technology: Enhances reliability and performance through innovative wafer bonding.
Applications for QLC Flash
QLC flash is versatile and scalable, supporting a wide range of use cases:
- Client and consumer SSDs
- Nearline HDD replacement
- Data centers and cloud storage
- AI-related workloads
Looking Ahead
QLC flash represents a sweet spot in today’s storage landscape, delivering high capacity, competitive cost, and solid performance for read-intensive applications. While it will not replace every type of NAND, its increasing maturity and ongoing innovation make it a core part of Kioxia’s vision for the future of high-capacity storage.
Stay tuned, in our next Flash Memory Matters post we’ll explore QLC flash further by highlighting the Kioxia SSDs that feature the technology.
Notes
1: As of July 3, 2024. Kioxia survey.
2: https://www.kioxia.com/en-jp/about/news/2024/20240703-1.html
In every mention of a KIOXIA product: Product density is identified based on the density of memory chip(s) within the Product, not the amount of memory capacity available for data storage by the end user. Consumer-usable capacity will be less due to overhead data areas, formatting, bad blocks, and other constraints, and may also vary based on the host device and application. For details, please refer to applicable product specifications. The definition of 1KB = 2^10 bytes = 1,024 bytes. The definition of 1Gb = 2^30 bits = 1,073,741,824 bits. The definition of 1GB = 2^30 bytes = 1,073,741,824 bytes. 1Tb = 2^40 bits = 1,099,511,627,776 bits.
Definition of capacity: KIOXIA Corporation defines a kilobyte (KB) as 1,000 bytes, a megabyte (MB) as 1,000,000 bytes, a gigabyte (GB) as 1,000,000,000 bytes,a terabyte (TB) as 1,000,000,000,000 bytes, and a kibibyte (KiB) is 1,024 bytes. A computer operating system, however, reports storage capacity using powers of 2 for the definition of 1GB = 2^30 bytes = 1,073,741,824 bytes and 1TB = 2^40 bytes = 1,099,511,627,776 bytes and therefore shows less storage capacity. Available storage capacity (including examples of various media files) will vary based on file size, formatting, settings, software and operating system, and/or pre-installed software applications, or media content. Actual formatted capacity may vary.
Read and write speeds are the best values obtained in a specific test environment at KIOXIA and KIOXIA warrants neither read nor write speeds in individual devices. Read and write speed may vary depending on device used and file size read or written.
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