Why is an SSD more expensive than an HDD?

If you’ve ever looked at buying a new hard drive or upgrading your computer, you’ve probably noticed that SSDs cost more per gigabyte than HDDs. A 2TB HDD might cost $80. A 2TB SSD costs $180 or more. Same storage capacity, very different price. Here’s why.

How an HDD Works

A traditional hard drive is a mechanical device. Inside the metal casing are one or more spinning platters coated with a magnetic material. A read/write head mounted on an arm moves across the platters to read and write data, similar in principle to an old record player needle on a vinyl record.

The platters spin at either 5400 RPM or 7200 RPM depending on the drive. The head physically moves to the location on the platter where the data is stored. This mechanical movement takes time. It’s called seek time and latency and it’s measured in milliseconds.

HDDs have been made this way since the 1950s. The technology is mature, the manufacturing process is well understood and the components are relatively cheap to produce at scale. Spinning platters, magnetic coating, a motor, a read/write head and the electronics to control it all.

Common HDD brands you’ll see in computers include Seagate, Western Digital and Toshiba. A typical 7200 RPM desktop HDD delivers sequential read speeds of around 150 to 200 MB/s. A 5400 RPM laptop drive does around 100 to 130 MB/s.

How an SSD Works

An SSD has no moving parts at all. Data is stored in NAND flash memory chips, the same type of technology used in USB drives and phone storage, just faster and more densely packed.

When data is read or written, electrical signals pass through transistors in the NAND cells. No mechanical movement, no spinning platters, no read/write head travelling across a surface. The result is access times measured in microseconds rather than milliseconds. Hundreds of times faster for random read and write operations.

A SATA SSD like the Samsung 870 EVO or Crucial MX500 delivers sequential read speeds of around 550 MB/s. An NVMe SSD running on the PCIe interface, like the Samsung 990 Pro or WD Black SN850X, delivers sequential reads of 7,000 MB/s or more. That’s the same interface standard used in the most demanding storage applications available right now.

The NAND flash chips inside an SSD are the expensive part. They’re semiconductor components manufactured in specialist fabrication plants using processes similar to those used to make CPUs and GPUs. The equipment required to manufacture NAND flash at scale costs billions of dollars. The process is complex and yield rates, the percentage of chips that come out of the manufacturing process working correctly, affect the cost of every chip that reaches the market.

Why NAND Flash Costs More Than Magnetic Storage

Manufacturing complexity

HDD platters are manufactured using relatively established processes. The precision involved is significant but the technology has been refined over decades. NAND flash manufacturing involves laying down semiconductor structures at the nanometer scale. Modern 3D NAND stacks dozens of layers of memory cells vertically, sometimes over 200 layers in current generation products from Samsung, SK Hynix and Micron. Each layer has to be deposited, etched and verified with extreme precision.

Fab costs

The fabrication plants that produce NAND flash are among the most expensive industrial facilities ever built. A modern semiconductor fab costs $10 billion or more to construct and equip. Those capital costs are reflected in the price of every chip that comes out of them.

Controller chip

Every SSD has a controller chip that manages how data is written, read and distributed across the NAND cells. The controller handles wear levelling, which spreads writes across the NAND to prevent any single cell from wearing out too fast, error correction, garbage collection and the interface between the drive and the host system. Controllers from companies like Phison, Silicon Motion and Samsung’s in-house MJX controller are purpose built semiconductor components. That’s another cost that HDDs don’t have in the same way.

DRAM cache

Most decent SSDs include a DRAM cache buffer, usually DDR4 or LPDDR4, that stores a mapping table of where data is located on the NAND. This speeds up read operations dramatically. A 1TB SSD typically has around 1GB of DRAM cache. Budget SSDs skip the DRAM cache to reduce cost, which is why DRAM-less SSDs like the Crucial P3 are cheaper but slower under sustained load than drives like the Samsung 870 EVO or WD Blue SN580.

Market supply and demand

NAND flash prices fluctuate with global supply. When demand outstrips production capacity, prices rise. When fabs overproduce, prices fall. SSD prices have dropped significantly over the past five years as 3D NAND manufacturing has matured and production capacity has expanded. A 1TB SATA SSD that cost $250 in 2018 now costs around $90 to $120. But HDDs have also dropped, so the gap hasn’t closed completely.

SSD vs HDD — What You Actually Get for the Price Difference

The price difference between an SSD and an HDD buys you several things.

Speed. A SATA SSD is four to five times faster than a 7200 RPM HDD for sequential operations and orders of magnitude faster for random read and write operations. An NVMe SSD is fifty times faster than an HDD. Boot times that took three to five minutes on an HDD drop to 20 to 30 seconds on an SSD.

Reliability. HDDs fail mechanically. The read/write head can crash into the platter surface. The motor can fail. The platters can degrade. Drop an HDD while it’s running and you may lose data. SSDs have no moving parts to fail this way. They’re more resistant to shock and vibration. Average failure rates for SSDs are generally lower than for HDDs over a three to five year period, though NAND cells do have a finite number of write cycles.

Noise and heat. HDDs produce noise from the spinning platters and moving head, and generate heat from the motor. SSDs are silent and generate less heat.

Form factor. NVMe SSDs in the M.2 form factor are tiny. The Samsung 990 Pro is a small card that sits directly on the motherboard. This allows for thinner, lighter laptops and cleaner desktop builds without cables.

Power consumption. SSDs use less power than HDDs. Important for laptops where battery life matters.

When an HDD Still Makes Sense

Despite all the advantages of SSDs, HDDs still have a place.

Mass storage. A 10TB or 16TB HDD for storing large video files, photo archives or backups is still far cheaper than an equivalent SSD. For data that doesn’t need to be accessed quickly, the cost per gigabyte of an HDD is hard to beat. A 4TB Seagate Barracuda costs around $100. A 4TB Samsung 870 EVO SATA SSD costs around $350.

NAS and backup drives. Network Attached Storage devices and backup drives designed for always-on operation use purpose built HDDs like the Seagate IronWolf or WD Red series. These drives are engineered for 24/7 operation, multiple drive arrays and the vibration environment of a NAS enclosure. Equivalent capacity SSDs for this use case are significantly more expensive.

Secondary storage in desktops. A common setup is an NVMe SSD for the operating system and applications, paired with a large HDD for data storage. Fast boot and application load times from the SSD, cheap mass storage from the HDD.

Which Should You Choose for a Computer Upgrade?

For most Melbourne home users and small businesses upgrading a slow computer, the answer is an SSD for the operating system drive. Every time, without exception.

If your computer is still running Windows on a spinning Seagate or Toshiba HDD, replacing it with a Samsung 870 EVO or Crucial MX500 SATA SSD is the single most impactful upgrade you can make. Boot times, application load times and general responsiveness improve dramatically.

If your computer has an M.2 NVMe slot, a WD Black SN850X or Samsung 990 Pro will give even better performance.

If you need large amounts of cheap storage for files and backups, add an HDD as a secondary drive.

If you want a detailed recommendation for your specific computer, give us a call. We look at the machine, check what storage interface it supports, what the bottleneck actually is and recommend what makes sense for the budget.

You can read more about our computer upgrade services including SSD and RAM upgrades on our Computer Upgrades Melbourne page.

Case Study

Slow Desktop Fixed With SSD Upgrade — Mount Waverley

A customer from Mount Waverley called us about a desktop PC he used for his small drafting business. It was an Intel Core i7-6700 machine he’d bought in 2016, running Windows 11 with 16GB of DDR4 RAM. Plenty fast enough for the work he was doing in AutoCAD and Microsoft Office but painfully slow to start up and slow to open large files.

He’d been told by someone he should replace the computer. He wasn’t convinced.

We came out and ran diagnostics. CPU was fine. RAM was fine. CrystalDiskInfo on the storage showed a Seagate Barracuda 1TB 7200 RPM HDD with 55,000 power on hours and a health rating of 68 percent. Drive was getting old but the bottleneck was the spinning drive, not anything else.

Sequential read speed on the Seagate was 142 MB/s. Sequential write 138 MB/s. Normal for a 7200 RPM drive. But random 4K read speed, which is what matters for Windows boot and application load times, was 0.6 MB/s. That’s the fundamental limitation of a spinning drive. The head has to physically move to each random location on the platter.

We recommended a Samsung 870 EVO 1TB SATA SSD. His board was a Z170 chipset without an M.2 slot so SATA was the right interface for this machine.

Cloned the existing Seagate to the Samsung 870 EVO using Macrium Reflect. Full system clone including the Windows installation, all his AutoCAD files and project data. Swapped the drives, booted from the Samsung, verified everything was working. Ran a quick Macrium verification to confirm the clone was clean.

Sequential read on the Samsung 870 EVO came up at 548 MB/s. Sequential write 503 MB/s. Random 4K read at 98 MB/s. A 163 times improvement in random read performance compared to the old Seagate.

Boot time before the upgrade was 4 minutes 20 seconds from power button to usable desktop. After the upgrade, 28 seconds.

AutoCAD opening a large drawing file he used as a benchmark went from 47 seconds to 9 seconds.

Total job was $195 including the Samsung 870 EVO 1TB SSD, the clone, the swap and testing. He’d been quoted $1,400 to $1,800 for a replacement machine by another supplier. The i7-6700 with an SSD and 16GB of RAM handles his AutoCAD workload without any issues.

He’s kept the old Seagate in an external USB enclosure as a secondary backup drive. Still spinning, just not the bottleneck anymore.

Summary

SSDs cost more than HDDs because NAND flash memory is a sophisticated semiconductor product made in some of the most complex manufacturing facilities in the world. HDDs are cheaper because magnetic storage technology is mature and the mechanical components are relatively inexpensive to produce.

The price gap has been closing for years and continues to do so. For operating system drives and performance storage, SSDs are the right choice for almost every use case. For cheap mass storage, HDDs still make sense.

If your computer is running on an old HDD and feels slow, an SSD upgrade is very likely the fix. Read more about our SSD upgrade service on our Computer Upgrades Melbourne page or call us on 0484 357 559.