When it comes to storage, two common options are hard disk drives (HDDs) and solid state drives (SSDs). Both have their own pros and cons and are suited for different use cases. So which one is better – HDD or SSD?
Quick Overview – HDD vs SSD
HDDs use spinning magnetic disks to store data. They have been around for decades and are inexpensive per gigabyte compared to SSDs. However, they are slower, more prone to failure due to moving parts, and suffer from fragmentation issues over time.
SSDs use flash memory chips to store data. They are much faster than HDDs, more durable with no moving parts, and avoid fragmentation problems. However, SSDs are more expensive per gigabyte and have limited write durability compared to HDDs.
| HDD | SSD |
|---|---|
| Cheap per GB storage | Faster read/write speeds |
| Slower speed due to physical moving parts | No moving parts, more durable |
| Prone to fragmentation over time | Avoid fragmentation issues |
Storage Capacities
When it comes to how much data can be stored, HDDs offer far larger capacities than SSDs. Currently, HDD capacities top out at around 16TB for consumer models and up to 20TB for enterprise drives. On the other hand, consumer SSDs currently max out at around 8TB, while enterprise SSDs can reach around 30TB.
If you need massive amounts of storage space, such as for backups, media libraries or data archives, HDDs provide much higher capacities at lower costs. The tradeoff is slower performance compared to SSDs. For most general consumer use cases though, SSD capacities up to 1TB are sufficient.
Performance and Speed
One of the biggest differences between HDDs and SSDs is performance. SSDs are much faster due to not having any moving parts and using NAND flash memory instead of magnetic discs to store data.
HDDs have spinning discs (platters) inside and movable read/write heads. This mechanical nature means they have slower random read/write speeds, usually in the range of 50-150MB/s. SSDs don’t rely on moving parts and can achieve random read/write speeds up to 500MB/s or more.
The table below compares the sequential read/write speeds of typical consumer HDDs vs SSDs:
| HDD | SSD | |
|---|---|---|
| Sequential Read Speed | Up to 210MB/s | Up to 550MB/s |
| Sequential Write Speed | Up to 210MB/s | Up to 520MB/s |
As a result of the faster speeds, SSDs have much lower latency and access times than HDDs. This makes them feel far more responsive for typical consumer workloads like booting an operating system, launching programs, opening files, transferring data, etc.
Durability and Reliability
HDDs are mechanical devices so they are inherently more prone to damage and failure over time due to wear and tear. Dropping a HDD can damage internal parts. The moving discs and heads mean more components that can fail.
SSDs have no moving parts, making them more durable and shock-resistant. They have up to 1500x more tolerance for vibration and drops. SSDs are not impervious to failure, but on average they tend to be more reliable and last longer than HDDs.
However, SSDs have a limit on how many times data can be written to each memory cell before wearing out. Consumer SSDs are typically rated for at least 500 total terabytes written. Under normal usage most regular consumers are unlikely to reach this limit. Heavy workloads like video editing, databases, server applications etc require higher-endurance SSDs designed for more write cycles.
Fragmentation
On HDDs, data is stored in sectors on the magnetic platters. When a file is deleted or modified, these sectors get freed up and scattered all over the drive. New data gets written into these blocks. This piecemeal storage over time leads to fragmentation issues, where parts of a file may be scattered in different locations on the HDD.
This fragmentation causes HDDs to slow down in performance over time. Files take longer to access since the drive has to scan multiple locations to retrieve all the blocks for the requested file. Defragmentation needs to be run periodically to reorganize and optimize data blocks on HDDs.
SSDs don’t suffer fragmentation issues like HDDs. The flash memory cells are all alike and wear evenly. When data is deleted or modified, the SSD simply marks those cells as available for new writes. This avoids data getting scattered over time. SSDs maintain consistent performance over their lifetime.
Noise
HDDs contain moving parts like the spinning platters and the read/write arm actuator. This mechanical nature means they generate audible noise during operation. The noise is a characteristic hum or whine from the motor spinning the platters.
SSDs have no moving parts. They operate completely silently with no motor or spinning platters. This makes them preferable for noise-sensitive environments. A silent PC build requires using SSDs over HDDs.
Boot/Load Times
Operating systems and programs load significantly faster from SSDs compared to HDDs. This is easily noticeable when comparing boot times on a PC with the OS installed on either drive type.
HDDs result in boot and load times ranging from 30 seconds to over a minute in many cases. SSDs can boot systems and load programs in under 15 seconds thanks to the faster speeds.
Likewise game and level load times are impacted substantially. Reading data from SSDs is much faster, so games see dramatically reduced load times. Most modern PCs benefit greatly from having at least a small SSD to host the operating system.
Lifespan
Being mechanical devices, HDDs have a finite lifespan and will eventually fail due to mechanical wear or component failures. However most last between 2-5 years with average use. Enterprise/RAID HDDs rated for 24×7 operation have an annual failure rate around 4% depending on workload and operating environment.
SSDs have a virtually unlimited lifespan in terms of read operations. However, there is a limit on the number of times data can be overwritten on each memory cell before wearing out – typically around 500-5000 full drive writes. Even accounting for that, most SSDs last 5-10 years for consumers. Enterprise SSDs have higher endurance ratings of 1-10 full drive writes per day for 5 years.
Power Consumption
HDDs need to spin a motor all the time power is supplied, so they consume more power overall. Desktop HDDs use around 6-8 Watts on average when active.
SSDs consume only a fraction of the power at idle and when active – averaging under 2 Watts for typical drives. This makes SSDs better suited for laptops to preserve battery life. A SATA SSD can extend laptop battery runtime by around 30 minutes compared to a HDD.
Encryption
SSDs usually have built-in encryption hardware to enable full drive encryption. Many HDDs lack this, so implementing full disk encryption on them has a performance penalty.
SSD encryption makes it easy to protect data on lost or stolen devices. Full disk encryption comes standard on most business/enterprise SSDs, while consumer SSDs often have optional TCG Opal compliance for full drive encryption.
Price and Cost Per GB
HDDs continue to offer the lowest storage costs per gigabyte. High capacity HDDs are available at under $0.03/GB. External portable HDDs in the range of 4TB can be purchased for under $100.
SSDs are more expensive at around $0.20/GB for smaller drives and $0.10/GB for higher capacity ones. The 1TB to 4TB range suitable for most consumers currently costs around $100 to $400. Prices keep dropping gradually, making SSDs more affordable.
For the same amount of money, HDDs can provide 5-10x higher raw capacity. However, the benefits like speed,silence, durability and power efficiency make SSDs worth the premium cost for most users.
Availability of Data Recovery Services
Due to mechanical failures being relatively common, HDD data recovery services are widely available. Recovery of data from mechanically failed HDDs is possible in most cases, albeit expensive.
SSD failures are less frequent on average, but the data is less retrievable compared to HDDs. The flash memory cells get permanently damaged over time or can get corrupted by sudden power loss. This makes full data recovery from dead SSDs difficult and costlier.
Conclusion
For most home and office users needing good all-round performance for OS, applications and primary data storage, SSDs are the better choice despite the higher cost. The speeds, silence, durability and efficiency of SSDs easily justify the premium over HDDs for primary storage.
HDDs are still preferred in use cases like secondary data storage, backups, archives and other read-intensive workloads where capacity is important and performance is secondary. The low cost per gigabyte of HDDs makes them ideal for high capacity storage.
For frequently written data like OS and apps, SSDs provide substantial benefits. While a hybrid setup with SSD for primary storage and HDD for additional data is a popular choice, SSD-only systems are becoming common with the declining costs.
In summary:
- SSDs are better for performance (faster, run silent, use less power)
- HDDs are better for capacity (larger storage for less money)
Choose SSDs for your OS drive, programs and games to get the best experience. Use HDDs for mass data that doesn’t need quick access – videos, music, images, documents, backups, etc. Both serve different roles and combining them gives a balanced storage solution.