SSD vs. HDD Performance Overview. How reliable are ssd

If you’ve ever used a computer with a hard drive before, you may recall the spinning sound. This sound comes from the cymbals. The plates must rotate in order for the computer to retrieve the data stored on them. There are no spinning platters in SSDs. As a result, SSDs can read and write data faster than hard drives.

SSD vs. HDD Performance Overview

Whether businesses are in the desktop, laptop, or server market, selecting the right storage solution is an important part of the process. By investing in a storage technology that suits your specific needs and the needs of your customers, you can enjoy greater speed, greater efficiency and reliable endurance.

However, deciding which storage solution is best can be difficult. With the two main options on the market today – solid state drives (SSDs) and hard drives (HDDs) – you’ll need to do your homework to understand the ins and outs of each. And while both have their advantages and disadvantages, it is clear that the market is currently in a transition period. While hard drives have been the first choice of choice in the past, SSDs are increasingly the choice of advanced developers and next-generation technology.

This means that Managed Service Providers (MSPs) and their customers should consider their specific requirements when selecting the storage solution that best fits their business. While SSDs tend to be the latest and greatest, the technology itself isn’t necessarily as mature as hard drives. Conversely, while hard drives are generally more affordable and commonplace, it is up to decision makers to judge whether it is wise to invest in an option that may begin to be phased out.

Regardless, the best solution for you and your clients depends on what gaps you want to fill. For some teams, newer SSDs will be a natural choice. For others, tried and tested hard drives may still make sense. To this end, we’ve compiled an overview of the key performance factors between SSD and HDD drives. If you’re getting ready to invest in your next storage solution or working with your customers to help them prepare, take the time to learn more about the decision that will have a big impact on IT operations.

Do SSD drives wear out?

The key consideration is the longevity of SSDs and hard drives. Computers encode information on hard disks in a write process that magnetizes and demagnetizes sectors with binary values ​​of ones and zeros. If for any reason this information needs to be overwritten, these sectors are magnetized and demagnetized in the same way. However, the process of writing SSD drives is significantly different, acting in such a way that they can eventually destroy the drive.

Encoding information on SSDs is complicated. They consist of flash memory cells similar to those that make up flash drives, although their capacity is much larger and they are more reliable than flash drives. To write information to these flash memory cells, SSDs transfer electrons to and from cells in a process called tunneling. While the process is faster than writing functions to hard drives, the downside is that tunneling gradually degrades the flash memory cells to the point where they do not function properly.

Additionally, electrons can get stuck in cell walls during the tunneling process. Over time, the accumulation of these electrons will make it difficult for the cell to efficiently store and access data. This means that in the long run, tunneling can also affect the ability of SSDs to reliably store data.

Taken together, these factors indicate that yes, the life expectancy of an SSD is limited; will wear out one day. Between the degradation caused by tunneling and the accumulation of electrons in the walls of flash memory cells when writing, reading, erasing, and rewriting data, at some point SSDs will no longer be usable or reliable in a manner suitable for consumer or commercial use.

This is also quite simple, although the name is a bit confusing. You might think this is a measure of how many times you can write data in a day, but it’s actually how many times you can rewrite an entire SSD in a day.

The Basics of SSDs

SSD is a data storage device characterized by the use of semiconductor chips. It is used for storing as well as reading non-volatile data.

SSDs differ from hard drives in their operation. While there are different types of hard drives, they all use magnetic discs called platters to store and read data. The planners rotate while the arm stores or reads data from them. SSDs do not have magnetic disks. Instead, they run on semiconductor chips.


The main advantage of using an SSD is speed. SSDs are noticeably faster than their HDD counterparts. According to Intel, SSDs offer up to 10 times faster read speeds and 20 times faster storage or write speeds than hard drives.

If you’ve ever used a computer with a hard drive before, you may recall the spinning sound. This sound comes from the cymbals. The plates must rotate in order for the computer to retrieve the data stored on them. There are no spinning platters in SSDs. As a result, SSDs can read and write data faster than hard drives.

The other part of NAND flash memory – flash – is a non-volatile solid-state memory that retains data even when the power source is disconnected. However, flash memory cells can only be programmed and erased a certain number of times which is measured in P / E cycles (meaning programmed and deleted).

How long does a SSD last?

SSDs are fairly new to the market which means manufacturers are still trying to figure out how long they’ll last. Currently, manufacturers use three different factors to estimate the lifespan of an SSD: SSD age, total terabytes written per time (TBW), and disk writes per day (DWPD). Based on the metric used, the answer to the question “How long do SSDs last?” It will be different.

For example, the age of an SSD has proven to be a valuable determinant of its performance and durability. Current estimates put the age limit for SSDs to be around 10 years, although the average lifespan of an SSD is shorter. In fact, a joint study by Google and the University of Toronto has been testing SSDs for many years. During this study, they found that the age of the SSD was a major determinant of when it stopped working. The researchers working on the study also found that SSDs were replaced approximately 25% less frequently than HDDs.

Another way to measure SSD endurance is the Total Terabyte Written Time (TBW). TBW estimates how many successful writes can be expected from a drive over its lifetime. If a manufacturer claims its SSD has a TBW 150, it means the drive can store 150 terabytes of data. Once your drive reaches this threshold, you’ll likely need to replace it.

The last of three metrics manufacturers can use to predict the life of their drives is the number of disk writes per day (DWPD). DWPD measures how many times users can overwrite the amount of available memory on a drive each day of its lifespan. For example, if an SSD has a capacity of 200 GB and is covered by a five-year warranty, users can write to the 200 GB disk every day for the warranty period before it fails. When in doubt, you can use the online SSD Life Calculator to estimate SSD Life.

Do SSDs fail?

SSDs can crash, but in a different way to traditional HDDs. While the latter often fail due to mechanical problems, SSDs can fail due to the methods used to write information. To understand why and how SSDs fail, the first thing you need to do is to better understand how they process, store, and access information.

As mentioned earlier, SSDs use flash memory cells to store data. Thus, SSDs act almost like large flash drives, programming data on these cells, changing their electric charge. However, when the available memory on an SSD is full, the SSD can only add new information by deleting older data. This process is called the program / erase cycle or P / E cycle for short.

Importantly, each SSD has a limited number of P / E cycles. Each P / E cycle gradually degrades the memory of SSD cells until they eventually wear out. At this point, you will no longer be able to rely on an SSD to store information. While the gradual wear and tear of flash SSD cells does not represent the same type of failure as a hard drive mechanical failure, it does mean the drive will no longer be usable.

While SSDs can fail less frequently than hard drives, they have a higher error rate that can affect the end-user experience. For example, SSDs are relatively common with so-called unrecoverable errors. Research shows that more than 20% of SSDs create unrecoverable errors within four years, and 30% to 80% develop bad blocks. All these errors can affect data storage and lead to a successful failure.

The SSD vs HDD reliability index is determined by MTBF, which is the mean time between failures. This is one of the more difficult and less obvious reliability measurements. Before making any purchase, it is important to understand the failure rates of MTBF and solid state drives.

So, How Reliable is an SSD?

Let’s go back to the two questions we asked above.

Question 1: Do SSDs fail faster than HDDs?

Answer: It depends on the drive technology and how you use them. HDDs are better suited for some applications and SSDs for others. SSDs can be expected to last as long or longer than HDDs in most general applications.

Question 2: How long can we reasonably expect the SSD to work?

Answer: Ideally, an SSD should last as long as its manufacturer predicts (e.g five years), provided that the disk usage is not excessive for the technology being used (e.g using QLC in a high-count application). Please refer to the manufacturer’s recommendations to ensure that the way you use your SSD is for its best use.

SSDs are a different breed of animal than HDDs and have their strengths and weaknesses compared to other storage media. The good news is that their strengths – speed, durability, size, power consumption etc – are backed up by some pretty good overall reliability.

SSD users are much more likely to replace their storage drive as they are ready to upgrade to a newer technology, larger capacity, or faster drive than the drive needs to be replaced due to its short life span. With normal use, we can expect an SSD to last for years. If you replace your computer every three years, as most users do, you probably don’t need to worry about whether the SSD will last as long as your computer does. The important thing is whether the SSD drive is reliable enough that you won’t lose data throughout its lifetime.

As we saw above, if you pay attention to your system, you’ll get sufficient warning of impending disk failure, and you can replace the drive before the data is unreadable.

It’s good to understand how different SSD technologies affect their reliability, and whether it’s worth spending the extra money on SLC via MLC or QLC. However, unless you are using an SSD in a specialized application with more writes than reads as outlined above, simply selecting a good quality SSD from a reputable manufacturer should be enough to ensure your SSD will have a useful life.

Keep an eye out for any signs of crashes or bad sectors and of course make sure you have a solid backup plan no matter what type of drive you use.

You may be interested in another post from the SSD 101, SSD 101 series: How to upgrade your computer with an SSD drive.

About Roderick Bauer

Roderick has held positions in marketing, engineering, and product management at Adobe, Microsoft, Autodesk, and several startups. It is consulted with Apple, Microsoft, Hewlett-Packard, Stanford University, Dell, the Pentagon, and the White House. He was a member of Ford-Mozilla in the field of media and democracy in the Joint Cause in Washington, where he advocated a free, open and accessible Internet for all, reducing media consolidation and transparency in politics and media.

The SSD manufacturer will make these specifications available for their products and help you understand how long your drive can last and if the drive is suitable for your application.


3D NAND technology was originally developed by Intel and Micron. This type of NAND arranges 32 layers of memory cells, while V-NAND or Vertical NAND arranges 48 layers of memory cells.

These new technological advances have increased the capacity of the drives without changing production costs, while reducing power consumption by half and at the same time increasing the lifetime of the flat NAND memory.


Reliability and Understanding SSD Lifespan

“Are SSDs failing?” Well, that’s actually redundant because D stands for disks, but yes. Of course. Everything is failing. Rather, we should ask, “Do SSDs fail faster?” This is a bit more complicated though.

SSDs are more reliable in harsh environments than hard drives because they have no actuator arms or any moving parts. Consequently, SSDs can withstand accidental drops and extreme temperatures better than hard drives.

But that doesn’t mean all SSDs are the same. Fortunately, there are some measurements that are commonly used to tell us how reliable an SSD is. They are often visible in the description of the SSD when you buy it. We’ve already covered and used P / E cycles a lot, but there are 4 others (don’t worry, they’re not too complicated):

  1. TBW or terabytes written
  2. GB / day
  3. DWPD, or Daily Disk Writing
  4. MTBF, i.e mean time between failures

It’s also worth noting that when they are shown on the packages they are taken as a guarantee (after all, part of the equation uses the guarantee). As such, they are usually higher than expected, but often also lower than what an SSD can push into.

Think of it as a tire, it can ensure that it won’t only explode when driving on the freeway for 5 years or 50,000 miles, but it can last much longer.

TBW, Terabytes Written

The first few are relatively simple and can even be matched using mathematics. For example, TBW is a reference to the number of terabytes that can be written over the life of an SSD. In many cases, TBW is actually quite ludacris, and is a number that will never come close to hitting you; he would be much more likely to fail with old age.

Gigabytes Per Day

The name says it all. It is a measure of how many gigabytes you are writing / overwriting per day. Since most SSDs are built with the thought you’ll be using a few gigabytes a day – which won’t happen unless your PC is a workstation – you should be fine.

Drive Writes Per Day

This is also quite simple, although the name is a bit confusing. You might think this is a measure of how many times you can write data in a day, but it’s actually how many times you can rewrite an entire SSD in a day.

Working It All Out

Let’s take a look at the Samsung SSD 850 Pro SATA with a 10-year warranty which has a capacity of 128 GB, 256 GB, 512 GB and up to 1 TB. It is designed to support 150 terabytes written or 150 TBW. But according to Samsung, these SSDs can hold up to 600 TBW.

Now, if we are to do the math and calculate the endurance of this SSD in 10 years, this drive can read and write 40 GB of data a day. Regarding the actual situation where a regular office user writes from 10 GB to 35 GB per day, the warranty would expire until the 150 TBW limit is reached.

If we take TBW, we can use the equations (or online tool) to find both DWPD (.041) and GB / d (41).

MTBF, or Mean Time Between Failures

The SSD vs HDD reliability index is determined by MTBF, which is the mean time between failures. This is one of the more difficult and less obvious reliability measurements. Before making any purchase, it is important to understand the failure rates of MTBF and solid state drives.

Even the quietest hard drive will emit some noise when in use. (The disc platters turn and the read arm moves back and forth.) Faster hard drives tend to produce more noise than slower ones. SSDs do not make noise at all; are non-mechanical.

HDD Fails Differently from SSD, How Do We Compare Reliability?

Inside of the hard disk. Needle head for reading / writing hard disk

While theoretically a hard drive has an infinite write / read life as hard drives do not damage the storage medium when writing / erasing. SSDs physically degrade NAND flash during erasing / writing. But of course, hard drives can fail mechanically due to other things like a needle or read / write head hitting the disc, or a motor failure. The read / write head for hard drives floats on a layer of air particles and should never touch the spinning discs. They can touch on events such as shaking the hard drive while reading / writing.

So it’s not as simple as saying a hard drive or SSD is more reliable than the other. They both act in different ways and they both fail differently. And as always, no consumer-grade product will be as rigorously screened for defects as enterprise-grade products. In other words, there are a few misfires here and there for the small minority of consumers who buy HDD or SSD.

So, in order for us to be able to compare a hard drive to an SSD, we need to find some common bases to compare. How about overall endurance to failure, regardless of type?

When it comes to endurance, TechReport reveals that most consumer SSDs are able to withstand over 700TB read and write, and a few others can survive up to 2.5 pentabytes. They also found that TLC SSDs generally had less endurance than their MLC counterparts.

    1.1 TB saved before death 700 TB saved before read-only to protect data 800 TB saved before death 900 TB saved before death Amazing 2.4 PB saved before death

Compare that to Backblaze testing against their hard drives. Backblaze has kept up to 25,000 hard drives online for the past four years. Whenever their drive failed, they wrote it down and then placed it in a replacement. After four years, Backblaze has compiled detailed data on the failure rates of hard drives during the first four years of their life.

Hard drives seem to have three different “phases” of failure. In the first phase, which lasts 1.5 years, the annual failure rate of hard drives is 5.1%. Over the next 1.5 years, the annual failure rate drops to 1.4%. After three years, the failure rate will explode to 11.8% per year. In short, this means approximately 92% of drives will survive the first 18 months, and nearly all (90%) will reach three years later.

Extrapolating from these numbers, nearly 80% of all hard drives will survive to their fourth anniversary. Backblaze does not provide any data, but prominent engineer Brian Beach speculates that the failure rate is likely to remain at around 12% per year.

This means that 50% of hard drives will survive until their sixth birthday.

But how long will an SSD last?

While some people are concerned that SSDs have a limited number of reads and writes, in fact we already know that an SSD’s read / write limit takes a very long time with normal use. In fact, the limit of 700 TB or more of data. Given that SSDs typically come with a three to five year warranty, this means manufacturers assume you’ll be writing anywhere from 20GB to 40GB of data a day. To reach the 700 TB limit, you would need to write 40 GB of data every day for 17,500 days, or about 50 years. This doesn’t mean you can mistreat your drive, and it doesn’t mean your SSDs won’t crash due to other issues, but if you’re worried that your SSD will die because you use it too often, don’t.

General Rule for Backups

In the consumer world, accurate statistics, failure modes, and chances of recovery aren’t really the key parameters. In fact, the important thing is that both can fail irreversibly and without any prior signals. If you want specifics – then an SSD is likely to have a higher risk of total irreversible failure, while hard drives can often be restored at significant cost.

So instead of relying on one part to fail, you should use a sensible backup scheme like the always-so-popular 3-2-1:

  1. At least 3 copies of the data.
  2. On at least 2 different media.
  3. At least one off-site.

The first point protects you from only a moderately improbable problem with both the original and the copy – and if one copy fails, you’ll still have peace of mind as your data is still backed up.

The second point is to protect against a mass failure affecting a given type of memory. For example, an overvoltage killing all hard drives in the NAS – but a disconnected copy of the external hard drive is still fine.

The last point is basically disaster protection – to keep your data safe in the event of fire, tornadoes, floods, earthquakes and so on.

This probably rightly sounds like overkill, but you have to consider how much your data is worth to you.

As you can see, MTBF refers to the failure rate of a drive over its expected lifetime. This does not mean that a 1.2 million hour MTBF disk will last 1.2 million hours, and a 1.5 million hour MTBF disk will last 1.5 million hours (136 to 171 years, by the way).

Advantages and Disadvantages of SSDs and HDDs

Hard drives are still available on budget and older systems, but SSDs are now the rule of thumb on popular systems and high-end laptops like the Apple MacBook Pro, which doesn’t even offer a hard drive as a configurable option. On the other hand, desktops and cheaper laptops will continue to offer hard drives, at least for the next few years.

That said, both SSDs and hard drives do the same job: boot your system and store your applications and personal files. But each type of storage has its own unique characteristics. How are they different and why would you want to put one over the other?

SSD vs. HDD Pricing

SSDs are more expensive than hard drives on a dollar per gigabyte basis. An internal 2.5-inch 1TB hard drive costs between $ 40- $ 60, but as of this writing, the cheapest SSDs of the same capacity and format start at around $ 100. This translates to 4 to 6 cents per gigabyte for a hard drive, compared to 10 cents per gigabyte for an SSD. The differences are more drastic when you look at 3.5 inch high capacity hard drives. For example, a 12TB 3.5-inch hard drive that costs between $ 300 and $ 350 can cut the cost per gigabyte below 3 cents.

As hard drives use older, more established technology, they are likely to remain cheaper in the foreseeable future. While the price difference per gig closes between hard drives and low-end SSDs, those extra dollars for an SSD could put your system’s price tag over budget.

SSD vs. HDD Maximum and Common Capacities

Consumer SSDs rarely come in capacities greater than 2TB, and these are expensive. You are more likely to find 500GB to 1TB units as basic disks on your systems. While 500 GB is now considered the “base” hard drive capacity for premium laptops, pricing considerations can bring it down to 128 GB, or 256 GB for cheaper SSD-based systems. Users with large media collections or content workers will need even more with the 1TB to 8TB drives available in high-end systems. Basically, the larger the capacity, the more stuff you can store on your computer. Cloud storage can be good for storing files that you plan to share between your smartphone, tablet and computer,but local storage is cheaper and you only need to buy it once, not subscribe.

SSD vs. HDD Speed

This is where the SSD drives shine. A computer equipped with an SSD will start up in much less than a minute, often in seconds. The hard drive takes time to accelerate to its operational specifications and will still be slower than an SSD in normal use. Your PC or Mac with SSD starts up faster, starts up and runs applications faster, and transfers files faster. Whether you’re using your computer for play, school, or work, the extra speed can be the difference between finishing on time and running late.

Second point: fragmentation. Due to the rotating recording surfaces, hard drives work best with larger files that are arranged in contiguous blocks. In this way, the drive head can start and stop reading in one continuous motion. When hard drives start to fill up, fragments of large files end up crumbling onto the disc’s platter, causing the drive to suffer from so-called “fragmentation.” While the read / write algorithms have improved to the point where the effect is minimized, hard drives can still fragment, affecting performance. SSDs cannot do this, however, as the lack of a physical read head means the data can be stored anywhere without penalty. This contributes to the inherently faster nature of SSDs.

SSD vs. HDD Storage: Breaking It Out by User

Overall takeout? Hard drives win with price and capacity. SSDs perform best if speed, endurance, form factor, noise, or fragmentation (technically a subset of speed) are all the factors you consider. If it were not for the price and capacity issue, SSDs would be the winner.

But does an SSD or HDD (or a hybrid of the two) fit your needs? Let’s break it down:

Multimedia enthusiasts and downloaders: Video collectors need space, and with a hard drive, you can easily get up to 8TB or much more space.

Budget buyers: the same. Lots of cheap space. SSDs are too expensive for $ 300 PC buyers.

Graphics and engineering professionals: Video and photo editors fill up and consume memory faster than most other users. Replacing or adding a 2TB hard drive will be cheaper than replacing a 500GB SSD, although the gap is narrowing.

General Users: These people are nuts. Users who prefer to download or store large amounts of their own media files locally will still need a larger hard drive capacity; SSDs become more expensive for large collections of movies and music. But if you mainly stream music and movies online, purchasing a smaller SSD for the same money will give you a better experience.

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