Solid state drives (SSDs) and hard disk drives (HDDs) are two of the most common types of computer storage devices. Both have advantages and disadvantages when it comes to performance, longevity, and cost. A key difference between SSDs and HDDs is how quickly they can wear out and become unreliable after repeated write/erase cycles.
What is an SSD?
An SSD, or solid state drive, is a type of computer storage device that uses flash memory to store data. SSDs use microchips rather than magnetic platters like HDDs, allowing them to access data much faster. However, SSDs typically have less storage capacity than HDDs. Some key characteristics of SSDs:
- Faster read/write speeds than HDDs, allowing quicker boot times and program launches
- Lack of moving parts makes them more resistant to physical damage/shock
- Lower storage capacities than HDDs – often 512GB or less for consumer models
- Higher cost per gigabyte than HDDs
What is an HDD?
A hard disk drive (HDD) is a traditional spinning hard drive that uses platters coated with magnetic material to store data. HDDs have been used for computer data storage for decades. Key HDD characteristics include:
- Slower read/write speeds than SSDs due to physical moving parts
- Vulnerable to damage from drops/shock due to moving platters
- Much higher capacities available – frequently 1TB to 4TB for consumers
- Lower cost per gigabyte than SSDs
SSD Wear vs. HDD Failure Rates
One of the biggest differences between SSDs and HDDs is how they handle long term wear. HDDs rely on mechanical parts like actuator arms, spindles, and platters that can eventually fail after years of use. However, under normal conditions most HDDs can operate reliably for 3-5 years or more before mechanical failure occurs.
SSDs have no moving parts, so they aren’t vulnerable to mechanical failure in the same way. However, SSDs use NAND flash memory chips to store data. These chips can only withstand a finite number of write/erase cycles before they begin to wear out and become unreliable. Most consumer SSDs are rated for anywhere from 500 to 5,000 write cycles.
This doesn’t necessarily mean the SSD will fail after 500 writes, but its storage cells will begin to wear out and eventually some may fail to retain data. At that point, the SSD would need to be replaced. This lifespan is estimated based on writing completely full blocks of data, so the actual lifespan depends heavily on usage conditions.
Due to their reliance on flash memory, SSDs typically have a shorter expected lifespan than HDDs when it comes to years of average use. However, SSD failure rates are still generally fairly low during the first 3-5 years. Here is a comparison of estimated annual failure rates for SSDs vs HDDs:
| SSD | HDD | |
|---|---|---|
| Year 1 | 1.5% | 1.7% |
| Year 2 | 2.7% | 4.0% |
| Years 3-5 | 5.0% | 6.0% |
As the table shows, both SSDs and HDDs have relatively low annual failure rates during the first few years of use. By years 3-5, SSDs begin to show noticeably higher failure rates due to wearing out from writes. HDDs have more consistent failure rates but remain reliable for longer overall.
Factors That Impact SSD Wear vs HDD Lifespan
There are several factors that can influence how quickly an SSD may wear out compared to an HDD:
- Write Volume – The more data that is written and rewritten on an SSD, the faster its storage cells will wear out. HDDs aren’t impacted by write volume in the same way.
- Drive Usage – Is the drive used as a primary system/boot drive or secondary storage? Boot drives endure far more writes which hastens wear.
- Drive Capacity – Lower capacity SSDs typically have lower write endurance ratings, wearing out more quickly.
- File Types – Certain types of files, like videos, images and audio do not get rewritten frequently and have minimal impact on SSD wear.
- Encryption – Full disk encryption increases the number of write operations, which can speed up SSD wear.
- Over-provisioning – Extra unused storage space reduces write amplification, helping to minimize wear.
For HDDs, factors like operating temperatures and physical shock/vibration are bigger concerns than write volume when it comes to lifespan. However, no type of computer storage drive lasts forever. Both SSDs and HDDs have a finite lifespan when used regularly.
Maximizing SSD Lifespan
While SSDs have inherent limits on their write endurance, there are steps you can take to maximize their usable lifespan:
- Leave approximately 10-20% of your SSD’s storage capacity as free space to allow wear leveling.
- Enable the TRIM command in your operating system to help maintain write performance.
- Avoid filling up your SSD completely as it will reduce write speeds.
- Use your SSD as your primary OS and applications drive, storing data files, images, videos, etc on a secondary HDD instead.
- When possible, avoid repetitive writes of temporary files to your SSD.
- Consider using encryption selectively rather than encrypting your entire SSD.
- Utilize cloud or external storage for your backup needs instead of writing backups to your SSD.
Following these tips can help you maximize the usable life of your SSD. However, hard drive failures can still occur unexpectedly at any time with any storage device.
SSD vs HDD: Cost Per Gigabyte
One area where HDDs still have a clear advantage over SSDs is in cost per gigabyte. HDDs are significantly cheaper than SSDs when comparing the dollar-per-gigabyte cost of storage. Here is a table comparing current SSD and HDD costs:
| SSD | HDD | |
|---|---|---|
| 250GB | $45-75 | $25-40 |
| 500GB | $60-100 | $30-50 |
| 1TB | $90-150 | $40-60 |
| 2TB | $140-250 | $50-80 |
As you can see, HDDs are generally around 50% or more cheaper per gigabyte compared to SSDs for equivalent storage capacities. The price gap does narrow a bit at higher capacities, but HDDs still retain a substantial savings over SSDs.
When Are SSDs Worth the Cost Over HDDs?
With their higher wear rates and per-gigabyte costs, SSDs may not always be the best choice for every build or usage scenario. However, there are times when paying more for an SSD is worthwhile:
- Boot drives – Using even a small SSD as your primary boot/system drive will provide a significant speed boost over booting from an HDD.
- Noise reduction – SSDs produce no noise which can be desirable for quiet computing.
- Frequent transportation – Less risk of damage compared to a spinning HDD.
- Quick access needs – For storage of files you need the fastest access speeds for.
- Harsh environments – More resilience against dust, vibration, extremes of temperature.
For secondary storage and backup needs, HDDs are still perfectly suitable and provide plentiful storage capacities at low cost. But for your operating system drive or any storage with speed sensitivity, SSDs are often worth the premium.
SSD vs HDD: Speed Comparison
One of the key areas SSDs shine over traditional HDDs is their markedly faster read and write speeds. Here is a general comparison of average speeds for SSDs vs HDDs:
| SSD | HDD | |
|---|---|---|
| Sequential Read | 500+ MB/s | 100-200 MB/s |
| Sequential Write | 400+ MB/s | 100-200 MB/s |
| Random Read | 100k+ IOPS | 50-100 IOPS |
| Random Write | 100k+ IOPS | 50-100 IOPS |
As you can see, SSDs offer at least 2-3x faster sequential read/write speeds compared to HDDs. More dramatically, SSDs are up to 1000x faster in terms of random access read and write speeds.
Why does this matter? Faster sequential speeds help when transferring large files like videos, photos, ISO files, etc. But high random access speeds have an even bigger impact for typical consumer use cases:
- Faster boot up times – SSDs allow PCs to boot in seconds rather than minutes.
- Rapid application/game launch times.
- Nearly instantaneous file opening.
- Improved overall system responsiveness.
Upgrading to an SSD provides one of the biggest perceivable speed boosts when using a computer for common daily tasks like web browsing, office work, and gaming. HDDs are still fine for bulk secondary storage, but SSDs are superior in terms of performance and well worth the higher cost for primary storage.
SSD vs HDD: Reliability
When looking at SSDs vs HDDs when it comes to reliability, there are several factors to consider:
- Total lifespan – HDDs can potentially operate reliably for 5+ years, compared to 3-5 years typical of SSDs before wear begins causing problems.
- Resilience – SSDs are inherently more resistant to physical shocks/damage thanks to a lack of moving parts.
- Failure patterns – HDDs have steadily increasing chances of failure over time. SSDs maintain low failure rates at first but then failure risk ramps up after the 3-4 year mark.
- Data recovery – Recovering lost data is often easier with HDDs compared to SSDs.
Overall, HDDs tend to last longer in terms of total years of service life. But they are more prone to physical failure from shock events like drops or impacts during operation. SSDs maintain their robustness over time but have limitations on the total amount of data that can be written over their lifetime.
Neither storage device is necessarily more reliable when looked at alone. Having redundant backups of important data is wise regardless of whether you use an SSD or HDD as your primary drive.
Mitigating loss on SSDs
To help avoid unrecoverable data loss with SSDs, there are a few important measures you can take:
- Use overprovisioning to minimize write amplification and wear.
- Clone your SSD periodically to refresh data cells and extend usable life.
- Keep regular backups of critical files/data via cloud storage, external drives, etc.
Backups and drive cloning help protect against data loss regardless of your drive type. But they are especially important for SSD longevity.
Choosing the Right Storage Drive
So which is better overall – SSDs or HDDs? There is no universal answer that fits every scenario. You need to weigh the factors that matter most to you. Here are some general guidelines on choosing storage drive types:
- SSDs for your primary OS/apps drive. This is where you’ll see the biggest speed gains.
- Larger HDDs for secondary storage of bulk files, backups, archives, etc.
- For gaming PCs, use an SSD for your game library if load times matter.
- For normal office use, an SSD provides snappy system performance.
- For mission critical data, use RAID configurations of multiple drives for redundancy.
In servers and high-end workstations, a combination of SSDs and HDDs is common to balance speed and storage capacity. If money is no object, max out SSD capacities. Otherwise, use SSDs for priority items and supplement with HDDs as budget allows.
Conclusion
SSDs definitely wear out and become less reliable after as few as 3-5 years of heavy use. However, they offer much faster speeds and operational responsiveness compared to traditional HDDs. For this reason, many users still choose to use SSDs as their primary storage device despite their limited lifespan.
To get the best of both technologies, use SSDs for your operating system and apps, and supplement with larger HDDs for secondary storage. Maintain backups of important data regardless of drive type used. With the right balance of SSD and HDD storage devices, you can build PCs and servers tailored for both speed and capacity.