What are QLC SSDs?

At four bits per cell, quad-level cell (QLC) technology expands data capacity beyond single-level cell (SLC), multi-level cell (MLC), and triple-level cell (TLC) solid state drives (SSDs). The greater density provided by QLC drives enables more capacity in the same space, for a lower cost per gigabyte.

Why are QLC NAND SSDs needed now?

More data is being created, stored, and analyzed than ever before. High-growth segments in computing today—such as artificial intelligence (AI) and machine learning (ML), big data/analytics, hyperconverged infrastructure (HCI), high-performance computing (HPC), content-delivery networks (CDNs), cloud digital video recorder (cDVR), and cloud storage—all require access to ever-expanding data volumes. And because these workloads need rapid, high bandwidth access to data, they require read-optimized performance with low latency.

While hard disk drives (HDDs) have historically been the standard for warm storage, they are struggling to keep up with the demands for these read-intensive workloads. Additionally, HDDs require a significant footprint in the data center, which adds to space, power, and cooling costs.

TLC NAND SSDs, on the other hand, are a good fit for mixed and write-heavy workloads, but they are typically not as cost-effective and capacity-optimized for large-scale, read-centric data needs. With 33% more bits per cell than TLC NAND SSDs, and efficient form factors providing up to 61.44TB of storage, Solidigm QLC NAND SSDs enable both accelerated data access and high capacities (see Table 1).

Table 1. QLC SSDs: The sweet spot for read-intensive workloads

Solidigm QLC 3D SSDs: Unlocking the value of stored data 

Like TLC NAND SSDs, QLC NAND SSDs can saturate the PCIe 4.0 bus on the read side and have near-TLC-like latency and quality of service (QoS). This makes the drive orders of magnitude more responsive than HDDs (see Table 2).

Table 2. How QLC SSDs compare to HDDs and TLC SSDs

Modern workloads: Characteristics and storage needs

QLC SSDs are optimized for read-intensive workloads needing rapid access to vast datasets. Figure 1 shows examples of a range of workloads [7] that QLC NAND is well suited for based on I/O patterns.

Figure 1. QLC SSDs are optimized for read-intensive workloads

Modern workload characteristics

The unique characteristics of these workloads are detailed in Table 3, with call outs for the bandwidth, latency, endurance, pattern, and block size for each segment and a description of the workload.

Table 3. Best-fit QLC SSD segments and workloads

Extract more value from your data with Solidigm QLC 3D SSDs

Built on proven technology, Solidigm QLC 3D SSDs provide exceptional high-bandwidth, low-latency read performance to support modern business-critical workloads, including ML, AI, CDNs, analytics, and big data while helping to lower TCO compared to HDDs and TLC SSDs by consolidating the storage footprint and reducing operational costs. Visit our D5 Series page to learn more.