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SSD Vs HDD - Evaluating Premises of Most Popular Storage Solutions

Hard disk drives or HDDs have been around since 1956 when they were introduced by IBM.

Unlike CPUs which went through several stages of evolution (16-bit to 32-bit to 64-bit, single versus multi-cores, X86 versus ARM architecture) and witnessed profound changes in design, the HDD remained relatively the same with changes in capacity, RPM, and connectors.

SSD tech developed in the 1980s. By 1999, 18 GB SSDs were available. But they were prohibitively expensive.

Oddly enough, it was a flood in 2011 that caused this change. Tropical Storm Nock-ten wreaked havoc across Thailand that July. The southeast Asian nation produced 50% of the world’s HDDs until it made none.

Whatever supply was there was bought out by OEMs and early adopters tried SSDs. 

They were impressed, and the surge in demand sent SSD sales soaring.

Solid State Drives (SSDs) & Hard Disk Drives (HDDs) are secondary storage devices. They are non-volatile, meaning you can switch off the power but they would retain the data (as opposed to RAM which is volatile).

SSDs use transistor-based flash memory technology while HDDs work on the principles of magnetic data storage.

In this guide, we’ll do a thorough SSD versus HDD comparison. We’ll cover:

  • Key differences between SSD and HDD
  • SSD versus HDD in terms of costs, boot speed, lifespan, and speed
  • A tabulated comparison for quick analysis
  • Data recovery considerations for SSDs and HDDs
  • FAQs about SSD versus HDD

This information will help you choose the suitable storage media based on your requirement. In addition, we’ll also discuss the reasons for data loss in SSD and HDD, and the ways to recover data from such devices.

What is SSD?

A solid state drive or SSD stores data on flash memory chips. The data is stored in the form of electrical charges. SSDs do not have moving parts and thus the question of wear and tear does not arise. 

In many ways, an SSD is similar to a USB drive. They both use flash memory. However, they differ in how that memory is configured and accessed. 

Advantages of SSD  Disadvantages of SSD
Uses less power compared to HDD Is relatively expensive
Doesn’t vibrate or make noise while running (because it does not have moving parts)
 
Uses of millions of transistors which causes it to heat up
 
Is much faster than HDDs Poses a lot of challenges in data recovery
Is less prone to physical damage as it doesn’t have a motor and rotating platter Is more expensive than an HDD of the corresponding size.
Has a negligible access time of about 0.1 ms (as compared t 5-8 ms in case of an HDD)  

What is HDD?

HDDs are magnetic data storage devices. They’re made up of mechanical components such as a platter, read/write head, etc. HDD remains a highly popular storage device among a significant number of users. They offer enormous storage capacity at a fraction of the cost of an SSD. 

The platter is made of magnetic material. The read/write head can rearrange this to binary form: 0 and 1. The head is suspended roughly 3 nanometers above the platter. As the platter rotates, the head writes millions of binary digits on it. 

Advantages of HDD Disadvantages of HDD
 
HDD is less expensive (on a per TB basis). Because of mechanical design, it takes time to access the data
Data recovery is easy because of availability of tools & techniques Consumes more power to function than SSD
HDD does not heat up as much Makes noises and vibrates when in use
  File opening & boot time is more as compared to SSD

 

SSD vs HDD: A Comparison

In this section, we’ve compared SSDs with HDDs based on some major factors such as storage capacity, speed, cost, and reliability. The comparison given here would help you make the right decision in selecting a drive as per your preference.

1. SSD vs HDD Storage Capacity

HDDs are far more economically viable if you’re looking for massive storage space. The HDDs are available in a wide range of capacities ranging from 250 GB up to 18 TB. In addition, there are even larger capacities for enterprise use.

SSDs are also available in varying capacities and huge storage, but an SSD is much costlier than an HDD of the same capacity.

SSD Internal Parts


Thus, HDDs are a better choice over SSDs when your main motive is to store a huge amount of data.
 

HDD Internal Parts

2. SSD vs HDD Speed

Speed is the crucial difference between SSD and HDD.

HDD drives, no matter how sophisticated, are largely mechanical. The actuator arm literally moves (88 times a second) to find data on the magnetic platter stored in tracks 10 nanometers wide. In other words, there are kinetic components that imply slower speed.

The SSD, on the other hand, reads data from a transistor. There are millions of them (actually trillions would be more accurate) and each is either on or off. Eight 0s and 1s make a byte and the SSD can read these bytes at lightning speed (quite true since in theory electronic devices work at 20-50% of the speed of light).

Whereas a 7200 RPM SATA III HDD can max deliver 150 MB/s, an SSD working through the same SATA III port can deliver 550 MB/s.

Faster interfaces such as PCIe Gen 4 allow a state-of-the-art consumer grade SSD like Western Digital WD SN850 to attain 7000 MB/s (read) and 5300 MB/s (write). source 

Speed of different HDD models

HDD HDD Interface HDD Speed/RPM
Seagate BarraCuda SATA 6Gbps 7,200
Toshiba X300 SATA 6Gbps 7,200
WD VelociRaptor SATA 6Gbps 10,000
WD Blue Desktop SATA 6Gbps 54,00
Seagate Firecuda Desktop SATA 6Gbps 7,200

Speed of different SSD models

SSD SSD Interface SSD Speed
Samsung 850 Pro SATA III 6 Gbps

560MB/s read (256GB)

550MB/s write (256GB)

Crucial MX500 SATA III 6 Gbps

560MB/s read

510MB/s write

SanDisk Extreme Pro SATA III 6 Gbps

550MB/s read

520MB/s write

Transcend SSD370 SATA III 6 Gbps

560MB/s read (256GB)

460MB/s write (512GB)

SanDisk Extreme II SATA III 6 Gbps

550MB/s read

510MB/s write

3. SSD vs HDD Cost

While choosing a storage device the first thing that might strike your mind is the cost of the drive. Typically, for a given capacity, SSDs are much costlier than HDDs. You’d get a larger capacity at a much lesser price if you choose HDD. 

However, if you want a fair deal, you can go for SATA III SSDs which offer a high speed at a reasonable price. They’re pocket friendly as they’re much cheaper than PCIe or M2 SSDs and are not very costly in comparison with some HDDs of similar capacities.

4. HDD vs SSD boot time

The average booting time of an SSD-equipped laptop running Windows 10 is about 13-15 seconds. 

In the case of an HDD that is at least 30 seconds, even when the machine has been freshly formatted. For a laptop that has been in use for 2-3 years, booting from HDD can take ages. Of course, a lot depends on how many programs are starting up besides the OS. 

There are plenty of YouTube videos that show SSD vs HDD booting comparisons. While the HDD is yet to make its way past the splash screen, the SSD machine is ready for work. 

In plain words, the faster data transfer speed and reduced latency work wonder for booting from an SSD. 

5. SSD vs HDD lifespan

In normal usage the lifespan of an HDD is 3-5 years. That might seem to be low considering that a RAM stick lasts a decade and so does a CPU (unless overclocked).

It is not the 7200 RPM spinning that causes the wear but the power on-off cycle. 

An SSD lasts longer because there is no motor that is powered on-off. 

But every transistor has a limited number of write cycles (several thousand). That means an SSD has a limited life span but that limit might very well be 8-12 years in normal usage conditions. 

Of course, there are exceptions and there would be someone or other on Reddit commenting how they have a perfectly working 10-year-old Seagate HDD while the brand new Samsung SSD died after 2 years. 

6. HDD vs SSD reliability

Reliability is an important factor. Are you sure the device is rugged and would always power up?  

The reliability of an electronic device depends on multiple factors of which the most important is temperature.

Hard disks routinely operate at 50°C. It is best if they are at less than 40°C, but 50°C does not cause them to malfunction. Lower ambient temperature leads to a longer lifespan.

SSD drives can run really hot. A temperature of 70°C is common when writing intensively, such as the transfer of a high-definition movie.

It causes problems because no user can guarantee that the device would only be deployed in an air-conditioned environment with an ambient temperature of 22°C.

The use of heat sinks on new SSDs seems to be the way out. But that means from now on every desktop would need to have three heat sinks—one each for motherboard, graphics card, and SSD. Better case cooling would be needed to vent the warm air. That would mean new and larger cases and possibly bigger exhaust fans.

As far as laptops are concerned, it is not possible to have a case fan.

SSD is too new as a technology to know if a sufficient number fails inside a laptop. Most vendors of Windows laptops, e.g. HP, Dell, and Lenovo, continue to offer laptops with dual drives as a standard option (a small SSD and a larger HDD). A report from Backblaze states that SSDs are as reliable (or unreliable) as HDDs. Reports from Google say that SSDs are better. 

The other aspect is how long can SSD sustain data without power? Consumer-grade SSD need to be powered up once every year. Otherwise, the transistors lose their memory. HDD also needs to be powered up but after longer intervals. They have better archival ability. 

On the whole, an SSD might not be more reliable than an HDD as far as current data goes. It’s not as cut and dried as usual hardware comparisons - Core i3-550 from 2010 is better than Pentium Dual Core E6800 from the same year.

Remember that SSDs have not yet become ubiquitous. More usage and more studies are needed to reach a definitive conclusion.
 

Table depicting some differences between SSDs and HDDs:
 

Key Parameters HDD SSD
Access Time 5.5~8.0 ms 0.1 ms
Random I/O Performance Up to 400 io/s 6000 io/s
Reliability Failure Rate 2~5 % Failure Rate 0.5%
Energy Savings Consumes between 6 & 15 watts Consumes between 2 & 5 Watts
CPU Power Average I/O wait is 7% Average wait time is 1%
Input/Output Request Time Average time is 400~500 ms Average Service time 20 ms
Backup Rates 20~24 hours 6 hours

Before opting for SSD or HDD, consider the following factors:

  • For what purpose you want to use the drive?
  • How much money you are willing to shell out?
  • In which environmental conditions you’re going to keep the drive?
  • How you’re going to handle it?

Data loss can happen to both types of drives.

Neither SSD or HDD is exempt from drive failure. You might lose data because of malware, accidental deletion of files and partitions, or hardware failure of some kind.

An SSD is less susceptible to physical damage. If you drop it, it will probably run fine with no issue. HDDs are more delicate and suffer physical damage more readily.

In case you have suffered from loss of data in SSD or data loss from HDD, it is possible to retrieve it, but you need expert help.

Why is data recovery from SSD more difficult?

Because for decades the data recovery industry has learned from analysing failed hard disks. SSD has a rather aggrieve mechanism for deletion, known as TRIM. If TRIM is enabled, then all file deletions are followed by rewriting blocks to 0.

In the case of HDD, that does not happen. The file marker information is removed by the system, but not the actual data.

But trust Stellar Data Recovery to provide support and guidance if your SSD should fail. Stellar has proprietary research and able technicians. In tandem, we provide hard disk recovery support service like no one else.

Stellar Data Recovery


The algorithms mapping the logical addresses to physical media locations vary depending on the make & model of the SSD.

The use of controller technology in SSD drives makes SSD data recovery even more complicated.

Also Read : Data Loss Risks Associated With SSD Drives

Irrespective of the complexities, a professional data recovery expert can recover data from SSD and HDD. In case of data loss, you need to select a right data recovery service provider like Stellar® who has specialized tools, technique, and expertise to recover data from SSD and HDD drives.

Understanding TBW - A Crucial SSD Benchmark

Manufacturers do not mention write cycles in SSD specs. They prefer to mention TBW or TeraBytes Written. 

Typically a budget Cricual 250 GB SSD has a TBW of about 100. It is actually a range e.g. 70-120 but we chose the mean value. 

100 TB equals 100,000 GB. Thus the entire 250 GB drive can be fully written, erased and rewritten 400 times (250 * 400 = 100000). 

This would take years. At least 8-10 years by most estimates. 

The mid-range Samsung 870 EVO 500GB SATA has a TBW of 300. A 500 GB hard drive that can be written fully and erased 600 times (500 * 600 = 300000)! That is an impossible amount of data. 

It is more likely that the CPU, motherboard, OS, and peripherals would become outdated before an SSD reaches its theoretical end of life. The practical end of life is a different matter and depends on the purity of the silicon, the durability of controller circuits and other factors. 

 

Final Take On SSD vs HDD Debate
 

The requirements for data storage are changing. It is normal for a home user to download several GB daily. The average web page size has grown to 2 MB from a hundred KB earlier. Servers need to have a larger capacity. 

The level of workloads and infrastructure options has set off the need for storage devices with a spectrum of performance, capacity, device features, form factors, and prices.

Both HDDs & SSDs are here to stay and will continue to play an essential role in both big data & fast data settings. We may see SSD prices go down and innovations will open new possibilities for improved data storage solutions. Further, we may see an increase in the speed of HDDs in the coming time.

As storage devices evolve, the assessment and consideration will not be about HDD vs SSD but about finding the most appropriate solution to support your needs.

FAQ

Which is better: SSD or HDD?

SSD is newer technology. It is without doubt better at data transfer and consumes less power. They also have an inbuilt encryption service that provides safety.

Which lasts longer: SSD or HDD?

The jury is out on this one. Research from Backblaze would seem to indicate that SSDs break down at the same rate as HDD. The important caveat here is that the oldest SSD they had (when they published the data) was 33 months.

More time is needed to know if AFR (annualised failure rates) are significantly different.

At 14 months age, Backblaze reports that 1.38% of HDDs fail compared to 1.05% of SSDs. That is almost the same.

Will that be sustained at 24, 36, 48, 60 months? Only time will tell.


SSD or HDD which is more complex to recover data from?

It is harder to retrieve data from a failed SSD. An SSD does not work in the same way as a HDD.

The data is constantly shifted around blocks of transistors. This makes it harder to locate.

If the TRIM function is enabled the task is even harder. TRIM command rewrites empty blocks to 0.


SSD vs HDD, which should I buy?

For normal usage, home and office, an SSD is a far better option currently. SSD tech has become highly reliable and the prices of smaller drives (up to 1 TB) have declined. 

SSD vs HDD, which is better as a boot drive?

Good question. A boot drive needs to be fast. Hence SSD is better.

But it also uses a page file (a type of temporary RAM). On a Windows 10 laptop with a RAM of 8 GB, the page file size is typically 16 GB. Can that eat into TBW? If the laptop is turned on twice daily then it eats up 16 x 2 x 365 = 11680 GB or 11 TB in a year.

But with a 500 GB SSD, you have 300 TBW. That would take 25 years of page file operations.

So you can safely go ahead and use an SSD for boot drive.


What happens at the end of the TBW period?

Some blocks will start to fail. Otherwise, the controller circuit might die.

Does an SSD need backup?

Of course. SSD or HDD, any storage media needs a backup. There are older and newer storage media but no fail-safe media. 

I still want to opt for an HDD in 2022

That is perfectly fine. Most home users do not need the 2000 MB/s read/write of an SSD. If you are more comfortable with spinning platter hard disks, it should be your first choice. 

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