When it comes to data storage for computers, the two main options are solid state drives (SSDs) and hard disk drives (HDDs). Both have their advantages and disadvantages when it comes to performance, durability, price and more. This comprehensive guide will examine the key differences between SSDs and HDDs to help you determine which is better for your needs.
SSD vs HDD: How They Work
SSDs and HDDs store data differently, which results in major differences in speed and operation. An SSD uses flash memory chips to store data persistently. This flash memory is accessed much faster than the spinning metal platters found in traditional HDDs.
HDDs instead use rotating magnetic disks called platters to store data. A read/write head moves mechanically over the platters to access data. This gives HDDs much slower access times than SSDs, but allows them to store more data at a lower cost per gigabyte.
In an SSD, data is stored in memory chips made up of silicon microchips. These chips contain grids of tiny transistors that can be electrically charged to store data as bits – either 1 or 0. Accessing data on an SSD is much faster because it just requires applying voltage to the memory chips rather than waiting for a mechanical arm to locate data on a spinning platter.
Traditional hard drives instead use actual physical heads to read and write data to metal platters. The platters spin extremely fast while the head moves back and forth to locate data. This mechanical operation provides the “hard” in the traditional hard drive.
SSD vs HDD: Speed and Performance
One of the most noticeable differences between SSDs and HDDs is the speed and performance. SSDs are significantly faster than HDDs in almost every regard. Here are some speed comparisons:
SSDs have near instantaneous access times, usually under 0.1 milliseconds. HDDs require an average of 5-10 milliseconds to locate data on a platter. This means SSDs can access data up to 100x faster than HDDs.
Data Transfer Speeds
SSDs have significantly faster data transfer speeds thanks to the direct electrical connections of flash memory. SATA III SSDs can reach sustained read/write speeds of up to 550 MB/s. HDDs max out at sustained transfer speeds of around 100 MB/s due to physical limitations.
Upgrading from an HDD to an SSD provides one of the most noticeable performance gains – much faster boot times. SSDs can boot in under 10 seconds, while HDDs require 30 seconds or more in many cases. Quick boot times are critical for many users.
File Copying and Opening
Copying files or loading programs and files occurs significantly faster with an SSD since data transfer speeds are much higher. Large files and programs can open in seconds rather than the minutes required by HDDs.
In almost every standard measure of speed and performance, SSDs come out significantly ahead of HDDs. The table below summarizes the major differences:
|Access time (average)||0.1 ms||5-10 ms|
|Sustained transfer speed||Up to 550 MB/s||Up to 200 MB/s|
|Boot time||Under 10 seconds||30 seconds or more|
|File open times||Near instant||Several seconds|
SSD vs HDD: Durability and Longevity
In addition to performance, durability and lifespan are important factors when comparing SSDs and HDDs. HDDs can ultimately withstand more writes over their lifetime – but SSDs have become much more durable than earlier versions.
Earlier SSDs had issues with wear over time, limiting their useful lifespans. However, modern SSDs use more durable NAND flash memory chips and controllers. Current SSDs can withstand hundreds of terabytes written to them before failure. This makes SSDs durable for years of typical consumer usage.
HDDs do not suffer from the same wear issues as earlier SSDs. However, they still have fragile moving parts that make them more susceptible to irreparable damage from vibration or shock. HDD lifespans are typically rated for a few years of normal usage before mechanical failure becomes a risk.
While HDDs can withstand more writes, SSDs actually end up lasting longer in typical real-world usage. Because SSDs are faster, they are able to complete read and write operations quicker. This reduces wear over time. Typical SSDs can easily last 5-10 years of normal consumer use before replacement is recommended.
SSD vs HDD: Storage Capacity
HDDs still offer much larger maximum capacities of storage compared to SSDs. High capacity HDDs go up to 10-16 TB, while the maximum for consumer SSDs is around 4 TB.
Consumer SSD units are available with storage capacities ranging from 120 GB to 4 TB. High performance internal SSDs used in gaming PCs or for creative workflows are typically 1-2 TB. Standard SATA III SSDs for basic PC builds often range from 240 GB to 1 TB.
HDDs are still the choice for mass storage needs for things like media libraries and archives where huge amounts of data need to be stored at the lowest cost. HDD capacities range from 40 GB up to massive 16 TB enterprise hard drives.
If you need huge amounts of cheap storage, HDDs are the better choice. But for most typical consumer needs under 1-2 TB, SSDs offer major advantages. The table below compares maximum capacities:
|Storage Device||Maximum Capacity|
SSD vs HDD: Pricing
SSDs continue to carry a price premium over HDDs when comparing the cost per gigabyte. However, SSD prices have been dropping rapidly in recent years. For most typical consumer needs, SSDs are now very affordable.
Basic SATA III SSDs start around $100 for a 240-500GB drive. High performance NVMe SSDs for gaming and creative workstations run $200-$300 for 1-2TB. At the higher end, enterprise-class 4TB SSDs cost around $700-$800. While certainly more expensive than HDDs, SSDs have come down in price enough that they make sense for most PC builds.
Good budget HDDs can be picked up for around $40-50 for 1-2 TB models. Very high capacity 10-16 TB HDDs scale up to around $300-$500. While HDDs are cheaper per gigabyte, the dramatically better performance and durability of SSDs make them worth the premium for many users.
Here is a pricing comparison between equivalent SSD and HDD drives on a cost per GB basis:
|Storage Device||Capacity||Price||Cost per GB|
|Samsung 870 EVO SATA III SSD||1 TB||$110||$0.11 per GB|
|Seagate Barracuda HDD||1 TB||$43||$0.043 per GB|
SSD vs HDD: Noise and Vibration
With no moving parts, SSDs run completely silent and produce no vibration. HDDs have spinning metal platters and noise from the head movements.
SSD Noise and Vibration
SSDs have no moving parts, so they operate silently. There is no noise or detectable vibration from SSDs during any reading or writing operation.
HDD Noise and Vibration
The mechanical nature of HDDs means they produce audible noise during operation. Seek sounds from the head movement are noticeable in quiet environments. Some vibration is also emitted from the spinning platters. Neither are excessive, but HDDs are not silent like SSDs.
SSD vs HDD: Power Efficiency
SSDs consume much lower power than HDDs during operation. This provides benefits for battery life in laptops along with lower electricity costs over time.
SSD Power Efficiency
SSDs only consume power when data is actually being read from or written to the storage chips. This means power draw is extremely low during idle periods. Overall power usage is typically 30-80% lower than a HDD under real-world usage.
HDD Power Efficiency
HDDs require constant power draw to spin the platters and power the head movement. This means idle power consumption is much higher than an SSD. HDDs can use 5-10x as much power as a SATA SSD under load.
SSD vs HDD: Shock and Vibration Resistance
The lack of moving parts also makes SSDs more physically resilient than HDDs to shock, vibration, and movement.
SSD Shock Resistance
Without fragile moving parts, SSDs can withstand much higher shock forces than HDDs. Dropping a SSD has essentially no effect on its operation. This makes them ideal for laptops and mobile devices.
HDD Shock Resistance
The moving physical parts within an HDD can be permanently damaged by drops, movement, vibrations, and shocks during operation. HDDs must be treated carefully and protected more than SSDs.
SSD vs HDD: Size and Form Factors
The smaller physical size of SSDs provides more flexibility in design and upgrades for devices and computers.
SSD Form Factors
SSDs come in a 2.5″ notebook drive size as well as smaller form factors like m.2 for ultracompact devices and slots. External SSD enclosures also connect via USB-C and are about the size of a smartphone.
HDD Form Factors
HDDs come in larger 3.5″ desktop sizes as well as 2.5″ notebook sizes. External HDD enclosures are much larger and heavier than external SSDs. While HDDs are shrinking, SSDs still hold a size advantage in many computer designs.
SSD vs HDD: Reliability and Lifespan
Both SSDs and HDSs have good overall reliability if used appropriately. HDDs can withstand more total written data overall, while SSDs have lower risk of sudden failure.
Early SSDs had issues with sudden failure after heavy usage. However, modern SSDs with more durable NAND flash memory chips have very reliable overall lifespans. Tests show typical SSDs lasting over 200 terabytes written, or 5+ years of average usage.
HDD reliability is strong if protected from shocks, vibration, and power failures. Tests show HDDs lasting 4-6 years on average before mechanical failures develop. HDD lifespans are usually rated for 300-500 terabytes written.
SSDs have no mechanical parts to wear down over time. However, disabled memory cells can develop after heavy write usage, slowing performance. HDDs more often fail suddenly from mechanical issues. Overall, modern SSDs last long enough even for heavy users.
Ideal Uses for SSDs vs HDDs
There is overlap in situations where either an SSD or HDD can be used. But there are ideal use cases that make the most of their respective strengths.
Ideal Uses for SSDs
- PC/Mac Boot drive
- Gaming consoles and PCs
- Video/photo editing and other creative work
- Servers and data centers
- Desktop/laptop storage upgrade
Ideal Uses for HDDs
- Backups and archives
- Media storage for music/movies
- Gaming console storage upgrades
- Network attached storage (NAS)
- Surveillance recording storage
For most typical consumer SSD and HDD uses for desktop or laptop PCs, SSDs are now the better choice. The dramatically faster speeds, better durability, lower power usage, and smaller form factors make SSDs ideal for booting, programs, and games.
HDDs are still recommended for massive data archives and backups. The larger capacities available along with lower costs make HDDs ideal for huge storage needs where access speed is less critical.
For a typical laptop or gaming PC, pairing a smaller SSD with a larger HDD allows you to get the best of both worlds. Use the SSD for critical OS files, programs, and games for faster speeds. Then store data archives, documents, media and other files on a more affordable high capacity HDD.
Choosing between an SSD and HDD used to involve major tradeoffs in cost, capacity, and speed. But with SSD prices dropping and performance improving over HDDs, for most users an SSD is now the clear choice thanks to the faster speeds, better reliability, and more compact form factors characteristic of solid state storage.