There are several key reasons why traditional hard disk drives (HDDs) are generally much cheaper than solid state drives (SSDs). HDDs have been around for decades and are produced at massive scale, allowing manufacturers to keep costs lower. SSDs are newer technology and more expensive to produce. HDDs also have slower performance than SSDs, allowing them to be offered at lower price points for more budget-focused applications.
HDD Manufacturing Scale and History
Hard disk drives have been around since the 1950s, giving manufacturers decades of experience in mass production. HDDs were the standard storage technology for computers for many years, allowing factories to refine manufacturing processes and achieve economies of scale. By contrast, SSDs only started becoming popular for consumer devices in the late 2000s.
Having mature production methods allows HDD manufacturers to negotiate lower prices on components, optimize factory throughput, and amortize equipment costs over many years. These savings directly translate to lower prices for consumers. HDD manufacturers have also consolidated over the years, with Seagate, Western Digital, and Toshiba accounting for most of the market. This lack of competition enables HDD makers to focus on operational efficiency rather than competitive pricing.
SSD Manufacturing Scale and Novelty
SSD manufacturing is a much newer industry without the decades of process refinement that the HDD industry has achieved. Only in the last 5-10 years has SSD production really scaled up to meet increasing market demand. Manufacturers are still working to maximize yields and optimize all aspects of the SSD production process to bring down costs.
Raw NAND flash memory chips, which make up the core of SSDs, are also expensive to manufacture. These chips must be fabricated in high-tech facilities that cost billions of dollars to construct. Facility investment must be recouped over the manufactured output, contributing to higher prices.
The SSD industry is also more competitively fragmented than the consolidated HDD industry. More competition puts pressure on manufacturers to reduce their profit margins through lower pricing. But this dynamic is counteracted by the higher relative costs of SSD production.
HDD Components are Cheaper than SSD Components
The mechanical architecture of hard disk drives utilizes inexpensive components, especially compared to the complex integrated circuits used in SSDs.
HDDs are constructed using:
- Aluminum or glass platters – Simple materials that are cheap to source and manufacture in high volumes.
- Magnetic coating – Applied as a thin film to the platters. Relatively abundant materials like cobalt are used.
- Spindle motor – Spinning the platters doesn’t require an especially powerful or precise motor.
- Read/write head – Tiny electromagnetic coil positioned on a suspension arm. More complex than the other parts but manufactured at scale.
- Legacy interfaces like SATA – Well-established standard so interfacing components are commoditized.
SSDs on the other hand require:
- NAND flash memory chips – Require advanced semiconductor fabrication processes and rare materials like lithium.
- Sophisticated controller chip – Complex integrated circuit that interfaces with the flash memory and hosts.
- Advanced interfaces like PCIe – Newer standards than HDDs that have less economies of scale for components.
The electronics involved in SSDs require more precision manufacturing and exotic materials that ultimately contribute to higher prices compared to the largely mechanical HDD.
HDD Factory Capital Costs are Amortized
Hard disk drive production equipment has been bought, paid for, and fully amortized over many years of operation. HDD factories are producing well-refined legacy technology on mature fabrication processes.
The enormous capital outlay required to build a semiconductor fab for NAND flash production is a significant factor in the price of SSDs. These fabs can cost over $10 billion to construct. This massive upfront investment must be recouped over the output volume of the fab.
Fabs also need to be upgraded every few years to implement higher density chips. Older hard disk drive production lines can run for much longer without major overhauls, keeping amortized costs down.
Economies of Scale in HDD Production
The hard drive industry’s immense economies of scale enable lower per-unit production costs. HDD makers have much greater production output than SSDs, allowing them to negotiate lower prices for components, amortize fixed costs over more units, and realize efficiencies in manufacturing.
According to estimates from Objective Analysis, in 2020 HDD manufacturers shipped:
- Western Digital – ~250 million HDDs
- Seagate – ~220 million HDDs
- Toshiba – ~64 million HDDs
Whereas SSD shipments from leading manufacturers in 2020 were:
- Samsung – ~73 million SSDs
- Western Digital – ~64 million SSDs
- Micron – ~34 million SSDs
The total HDD shipment volume is over 3x higher than SSDs. This allows the average cost per HDD to be lower.
HDD Manufacturing Processes are Mature
Hard disk drive engineering and fabrication have been optimized over 70+ years of cumulative experience. Manufacturers have finely tuned HDD production methods, supply chains, equipment maintenance, and quality control processes.
Any defects and inefficiencies have long been ironed out of HDD manufacturing. Yields are high, processes have been streamlined, and any waste has been minimized. This operational maturity helps keep HDD prices down.
SSD production is still maturing, in contrast. There are more opportunities left for enhancements in NAND fab operational efficiency. As semiconductor manufacturers refine SSD manufacturing processes, costs should decrease over time.
HDD Product Differentiation is Harder
Hard disk drives have become highly commoditized over the decades that they have been sold. There is little room left for HDD vendors to differentiate their products beyond basic performance attributes like capacity and spindle speed.
Most consumers treat HDDs as interchangeable between brands and models. This lack of differentiation pressures vendors to compete mainly on price, keeping profit margins lower.
SSDs are still an emerging technology category by comparison, giving vendors more opportunities to differentiate through performance, features, or industrial design. The additional customer value from those competitive differentiators allows SSD sellers to charge slight premiums over HDDs.
HDD Average Sales Prices are Lower
Hard drives have become a high-volume, low-cost commodity over their long history. The average selling price (ASP) that HDD manufacturers can charge PC makers and retailers is quite low.
By contrast, SSDs are sold in lower volumes and carry higher profit margins for manufacturers. The ASPs are generally several times higher than comparable HDDs when looking at a cost per gigabyte basis.
Here are some example ASPs for HDDs and SSDs in 2020, according to data from Coughlin Associates:
| HDD | ASP |
| 4TB 3.5″ 7200 RPM | $60 |
| 2TB 2.5″ 5400 RPM | $55 |
| SSD | ASP |
| 500GB 2.5″ SATA | $70 |
| 1TB M.2 NVMe | $117 |
Lower ASPs directly contribute to cheaper retail pricing for HDDs compared to SSDs on a per GB basis.
HDDs Have Slower Performance
Hard disk drives are physically limited in speed by their mechanical design. The moving platters and heads only allow data to be accessed sequentially at a rate of ~100-200 MB/s for today’s HDDs.
SSDs have no moving parts and can access data randomly at speeds over 1,000 MB/s for high-end models. This big performance advantage allows SSD manufacturers to keep prices higher while still providing more value from greatly improved speed.
HDDs cannot compete on performance, so they must offer much lower prices to compensate and appeal to budget-focused consumers.
Low-Cost HDD Applications Still Exist
Hard drives retain a cost advantage for applications that need huge amounts of lower-cost storage, do not require faster access speeds, or employ redundant drives. For example:
- Data archiving and backups
- Video surveillance recording
- Network attached storage
- Entry-level desktop PCs
These high-volume use cases sustain HDD volumes, giving manufacturers economies of scale. SSDs are preferred in performance-centric applications, while HDDs soldier on for bulk storage.
SSD Prices are Falling Faster than HDDs
SSD average selling prices have been declining much more rapidly than HDDs as manufacturing scales up. From 2020 to 2021, SSD ASPs dropped around 15-20% while HDD ASPs only fell 1-2%. This steep downward pricing trend makes SSDs more attractive compared to HDDs with every passing year.
Manufacturing optimizations and technical breakthroughs could accelerate SSD price drops even further. QLC NAND for 4-bits/cell and 5-bits/cell flash promise to boost density and lower costs. Improving wafer yields will also reduce waste and enable continued SSD price cuts.
Conclusion
Hard disk drives remain significantly cheaper than solid state drives today due to massive economies of scale, refinement over decades of production, maturity of manufacturing processes enabling low costs, and the mechanical nature of the technology. HDDs do not require rare materials or advanced semiconductor fabrication plants like SSDs.
However, the SSD market is developing rapidly, bringing down prices. Breakthroughs in flash memory production and advancing 3D NAND techniques will allow SSD costs to continue decreasing at a fast pace. The price gap between HDDs and SSDs is narrowing each year even as absolute SSD prices drop. For pure storage capacity, HDDs are likely to maintain a cost advantage, but SSDs are pressing into more markets on affordability.
