When choosing storage for a computer, the two main options are a traditional hard disk drive (HDD) or a solid-state drive (SSD). There are key differences between HDDs and SSDs in terms of performance, durability, price, and use cases. Understanding these differences can help determine which is the better choice for your needs.
What is a hard drive (HDD)?
A hard disk drive (HDD) is a traditional storage device that uses magnetic recording to store and retrieve digital data. It consists of one or more platters coated in magnetic material, which spin at high speeds. A read/write head floats just above each platter to access data as the platters rotate.
HDDs have been the predominant form of computer storage for decades. They offer large capacities at relatively low costs per gigabyte. HDD capacities currently range from 250GB to 16TB for consumer models. Enterprise and specialized HDDs can reach up to 100TB. The leading HDD manufacturers are Western Digital, Seagate, and Toshiba.
What is a solid-state drive (SSD)?
A solid-state drive (SSD) is a storage device that uses integrated circuit assemblies to store data persistently. Unlike HDDs, SSDs contain no moving mechanical parts. Instead, SSDs use microchips and memory chips to retain data electronically. The primary SSD technologies in the consumer market are NAND flash memory and NVMe (Non-Volatile Memory Express).
SSDs first became a viable consumer product in the late 2000s. Their early advantages were durability, silence, and low power consumption. In recent years, SSD prices have dropped significantly while capacities have risen, making them comparable to HDDs for more applications. Consumer SSD capacities range from 120GB to 8TB.
Hard drive vs SSD comparison
When considering HDDs vs SSDs, some key factors to compare include:
Price and capacity
HDDs are generally cheaper than SSDs when comparing raw storage capacities. A 1TB HDD costs around $40 while a 1TB SDD costs around $80. The price gap widens at higher capacities. For example, a 16TB HDD is around $300 while a 16TB SSD can cost over $2,000.
However, SSD prices have been dropping steadily. Lower-capacity SSDs often cost similar to HDDs. Also, the price per GB decreases on larger SSDs. A 4TB SSD is around $400, just 4 times more than a 1TB even though capacity is quadrupled.
Performance
SSDs are significantly faster than HDDs in almost every metric. Here are some typical performance comparisons:
| HDD | SSD | |
|---|---|---|
| Sequential read speed | Up to 200 MB/s | Up to 3500 MB/s (NVMe) |
| Sequential write speed | Up to 200 MB/s | Up to 3000 MB/s (NVMe) |
| Random read IOPS | Below 200 | Up to 600,000 |
| Random write IOPS | Below 200 | Up to 600,000 |
| Latency | 10-15 ms average | <0.1 ms average |
The speed advantages of SSDs make them far better suited for demanding applications like gaming, HD video editing, and running intensive programs.
Lifespan and durability
SSDs are more durable and longer-lasting than HDDs in typical use. SSDs have no moving parts and so are less susceptible to damage or wear from vibration, movement, and temperature fluctuations.
Consumer SSDs generally last around 10 years or more before needing replacement. HDD lifespan averages around 3-5 years, with higher failure rates over time. However, SSDs have a limit on the total amount of data that can be written to them, typically in the range of 600-800TB. The average consumer will unlikely approach this level for many years.
Noise and heat
HDDs require spinning platters and moving heads, which generate noise and heat. SSDs have no moving parts so make no audible noise and minimal heat. An SSD running silently may be preferable for certain environments like a bedroom or living room.
Shock and vibration resistance
SSDs have no risk of damage from shakes, drops, bumps, and vibration. HDDs can potentially suffer catastrophic data loss from a strong physical impact while operating. SSDs avoid this problem entirely. So SSDs are better suited for mobile use in laptops, tablets, or devices that may get frequently moved.
When should you choose an HDD over SSD?
While SSDs have many advantages, HDDs can still be a better choice in some scenarios:
- You need lots of storage capacity cheaply. For storage over 4TB, HDDs are much more cost effective.
- The device is rarely moved and safely stationary. HDD vulnerability to vibration isn’t a concern.
- You do mostly sequential data transfers. HDDs are still faster at sequential reads/writes.
- You won’t push the limits on speed. For light everyday computing, an HDD won’t hold you back.
In a budget desktop PC build or a stationary NAS (Network Attached Storage), large high-capacity HDDs still work very well while being affordable. HDDs also work fine in gaming PCs so long as you pair them with a smaller SSD for the OS and applications.
When should you choose an SSD over HDD?
SSDs outperform HDDs significantly in many usage scenarios. Situations where an SSD truly shines include:
- You regularly work with large files like video, photos, audio, etc. The faster speeds will save you time.
- You frequently boot up or launch programs. The faster startups of SSDs add up to lots of time saved.
- Your computer moves around or gets transported regularly. The durability and resilience of SSDs prevent damage.
- You play PC games, especially open world titles that stream assets. SSDs provide faster level loading.
- Noise is a concern. You want silent operation, which SSDs can provide.
For laptops and tablets, SSDs are almost universally the better choice. The performance, silent operation, and resilience of SSDs are essential benefits for mobile devices.
M.2 NVMe vs SATA SSDs
Solid-state drives come in two main interface types: SATA and NVMe. SATA has been the long-time standard for 2.5-inch SSDs. NVMe is a newer, faster standard using the PCIe bus through M.2 connectors. There are key differences:
| SATA SSD | NVMe SSD | |
|---|---|---|
| Interface | SATA | PCIe (M.2 connectors) |
| Sequential read speed | Up to 560 MB/s | Up to 3500 MB/s |
| 4K random read speed | Up to 100,000 IOPS | Up to 750,000 IOPS |
For peak performance, NVMe drives are the best SSD option. However, SATA SSDs still offer huge improvements over HDDs at lower costs. Even a SATA SSD at 500MB/s sequential read is around 2.5x faster than a hard drive.
Should you get an HDD, SATA SSD, or NVMe SSD?
With current prices, NVMe SSDs are the choice for premium desktop PCs and high-end laptops. SATA SSDs provide the best balance of price and performance for most mid-range and budget systems. HDDs still make sense for bulk storage needs.
Here are some general guidelines on choosing between drive types:
- NVMe SSD – For top-level performance in gaming rigs, workstations, high-end laptops.
- SATA SSD – Balanced option for mainstream laptops, mid-range desktops, budget gaming systems.
- HDD – For mass storage of files, creative work archives, backups. Use alongside a smaller SSD for boot and programs.
Hybrid SSHDs
A hybrid SSHD (solid-state hybrid drive) combines a small SSD with a large HDD in a single unit. The SSD acts as a cache to store frequently accessed data for faster speeds, while less accessed data remains on the HDD. Overall performance is better than a lone HDD but falls short of a full SSD.
SSHDs occupied a middle ground between SSDs and HDDs in the past. However, with SSD prices dropping steadily, pure SSD systems have become more attainable. For most people, a combo of an SSD and an HDD in laptop or desktop is a better solution than an SSHD.
External storage
Both HDDs and SSDs come in external formats for additional storage and backups. External SSDs connect via USB, Thunderbolt, or USB-C. They provide excellent portable storage, though at higher costs than external HDDs. External HDDs are a good choice for affordable mass storage for backups and archives.
RAID with HDDs and SSDs
You can combine multiple HDDs or SSDs together in a RAID (Redundant Array of Independent Disks) setup for increased speed, capacity, or redundancy:
- RAID 0 – Combines drives into a single large volume for increased performance. But there is no redundancy if a drive fails.
- RAID 1 – An exact copy of data is written to each drive for full redundancy. But usable capacity is only equal to one drive.
- RAID 5 – Data is striped across drives with distributed parity information. You get speed, capacity, and redundancy.
A common practice is to RAID together multiple HDDs for mass storage combined with RAIDed SSDs for increased speed. For example, two 1TB NVMe SSDs in RAID 0 would be very fast at 2TB total capacity. Or four 6TB HDDs in RAID 5 would give 18TB of redundant storage.
Which is more reliable HDD or SSD?
SSDs are substantially more reliable than HDDs for typical consumer workloads. SSDs have no moving parts, making them far less prone to wear and physical failure over time. Consumer SSDs today commonly last up to 10 years even with heavy daily use.
In contrast, HDDs have many mechanical parts including spinning platters, moving heads, motors, and bearings. The mechanical stresses lead to higher failure rates, especially as drive age increases. It’s very common for HDDs to start developing issues after only 3-5 years.
One reliability measure is annualized failure rate (AFR). Consumer quality HDDs have a typical AFR around 1-2% per year. Premium enterprise HDDs can reach as low as 0.7%. SSDs have much lower AFRs, commonly rated for 0.1-0.2% per year in consumer drives and even lower for enterprise models.
Overall, an SSD can be expected to outlast an HDD by 3x or more in typical home and office computing applications.
Do SSDs need special drivers?
In most cases, no special driver is required for an SSD. Windows, macOS, Linux, etc automatically detect and install SSDs as plug and play storage devices. However, you may want to check for a firmware update from the SSD manufacturer to ensure optimal compatibility and performance.
The exception is for NVMe SSDs. Windows 8 and newer natively support NVMe. Older versions of Windows and some Linux distributions may require you to install the NVMe driver manually.
Do SSDs need TRIM support?
The TRIM command helps maintain long-term performance on SSDs by clearing unused blocks of data. Without TRIM, unused data blocks can get cluttered over time, slightly slowing write speeds.
TRIM is natively supported in modern operating systems. You should enable TRIM if your OS supports it. In Linux, you’ll need to add the “discard” option when mounting the SSD’s file system.
Conclusion
SSDs are the superior choice over HDDs in almost every way – speed, durability, shock resistance, noise, etc. However, HDDs remain much cheaper for high capacity storage. The ideal solution for many PCs is an SSD paired with a larger HDD.
NVMe SSDs are blazingly fast and recommended for premium systems and performance storage. SATA SSDs offer a great balance of speed and price for mainstream computing. HDDs still work well for bulk data archives and backups.
Carefully examine your performance needs, capacity requirements, and budget when deciding between HDD vs SSD storage. By choosing the right drive types for your specific needs, you can build a PC or laptop that provides an ideal mix of speed, capacity, reliability, and value.