Whether you want to provision storage devices in the cloud or build your own computer, you’ll need a storage device. Currently, you have two options: a solid-state drive (SSD) or a hard-disk drive (HDD). Both types of storage are built and engineered differently, and they offer different benefits. SSD devices are faster, but they also cost more. HDD devices are slower, but they have a large storage capacity.


What’s the Difference Between SSD and HDD?

The foundation of speed difference is based on the physical properties of devices and the general laws of physics. SSDs are smaller because they’re circuits not unlike the USB devices that you plug into your computer. HDDs use spinning platters, which makes them heavier and larger than SSDs.

Because SSDs are made of circuits, they can be as tiny as a stick of gum, making them convenient and portable. They’re also more resistant to damage if you move a computer around or bump it against something. They don’t have the risk of data damage from magnets, so using one around something with strong magnetic fields (e.g., telephony equipment) won’t have a noticeable effect.

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HDDs contain stacks of spinning platters with a head that moves up and down as the platter spins. The head reads and writes data to the platters, which means that the speed of the platter determines the speed of data reads and writes. Data is stored magnetically, so a strong magnetic field could corrupt data. The distance between the head and the platter is smaller than the size of a speck of dust. To avoid damage from dust particles or any other small objects, HDDs are built in a dust-free clean room. 

An HDD is much more fragile than an SSD. If damage is done to the head and it touches the platters, it corrupts stored data. HDDs must be safely packaged when shipped and can easily break from exposure to the elements or any abrupt movements. Because the head is constantly moving across platters, HDDs have a higher chance of damage from mechanical failure.

SSD vs. HDD Speed: Which Is Faster?

The fastest HDD to date is the Seagate Exos, which offers 524MB/second speeds. The drive spins at 7,200 revolutions per minute (RPM), which is the fastest a physical object can spin. Achieving faster speeds is limited by the ability of platters to spin any faster than they currently do, but HDDs still have their purpose and advantages.

An SSD isn’t limited by spinning platters, so you get over 7,000MB/second transfer speeds. The speed transfers over 14 times faster, so it’s a noticeable advantage and speed difference for your computer. Even with the higher speed capacity, an SSD has its disadvantages over an HDD, depending on your application.

How to Measure SSD vs. HDD: Speed Tests

If you have both storage types installed, you’ll likely notice a speed difference because SSDs are much faster than HDDs. To determine the actual difference in speed, you’ll need to download benchmarking tools. Drive manufacturers, such as Crucial, Samsung, Intel, and SanDisk (Western Digital), provide benchmarking tools that enable you to test drive speeds.

How to Benchmark SSD vs. HDD

Storage devices are benchmarked using read and write actions. Cables can affect transfer speeds, but speeds are generally benchmarked by writing data to the drive and then reading data from the drive and timing both actions. SATA cables are used to connect both drive types, so it’s likely that one is connecting your drive to the motherboard. Using benchmarking software, you can identify read and write speeds for both HDD and SSD storage to figure out which one is faster.

Does SSD Read Faster than HDD?

HDDs are built to either store data and write faster or to read and write, such as those installed in a desktop computer. SSDs aren’t typically used for long-term backups, so they’re built for both but are typically used in speed-driven applications. A standard HDD will read and write at typically 80MB/s to 160MB/s, but an SSD reads and writes at between 200MB/s to 550MB/s. Newer technology introduced in recent years offers faster speeds but at a much higher price than a typical storage drive.

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Does SSD Write Faster than HDD?

An SSD is flash memory, so it also writes data faster than an HDD. Note that an SSD degrades over time when it overwrites data in read-erase-write actions. Overwritten data happens more frequently when the SSD fills up, so it’s generally considered good practice to keep plenty of free space open on the SSD. Also, HDDs can hold more data currently, so they’re preferred for long-term storage with fewer reads, such as storage reservoirs for disaster recovery and backups.

Which Is Better: SSD or HDD?

Traditionally, the biggest disadvantages of an SSD have been price, degradation, and capacity. SSDs are limited in cost per capacity, although they continue to catch up to their HDD competitors. Storage device technology changes every year, but currently, a 4TB SSD can cost several hundreds of dollars. Having one of these devices might not be too expensive, but having multiple ones may be too costly for some businesses. Another disadvantage is degradation. Every write action causes degradation on the drive, so it will eventually fail, making it important to have failover and backups.

Applications that require fast data transfers take advantage of SSDs the most. For example, you might have a high activity database server that must read and transfer data quickly to keep performance at optimal levels. An SSD can more quickly read data, store it, and transfer it from the drive to the computer process and memory. High-performance servers often use SSDs to deliver the necessary speed.

QLC vs. MLC: Which Is the Better SSD?

Because of their high-capacity storage capabilities and stability, HDDs are typically used as backup devices. Currently, HDD devices offer 12TB of storage capacity at a much more affordable cost than SSDs. Also, HDDs don’t have the write degradation issue that SSDs do. Backup devices don’t need fast transfer speeds because you won’t need to access the data often. They can be mirrored for failover and used to store as much data as you store on an SSD in case of a disaster. A network attached storage (NAS) device will have an array of HDDs to store data quickly and restore it should you need to recover from a disaster.

On the flipside, advances in SSD cost per capacity mean that for mission critical backups and higher performance applications especially in enterprise settings, SSDs have begun to close the cost per capacity gap between SSDs and HDDs. For this reason, some organizations are able to make a permanent switch from HDDs to SSDs for all their data storage needs.

To summarize, if you need a storage device for a personal computer or server hosting frequently used applications, an SSD is the best option. If you need to build backup storage equipment, an HDD will offer higher capacity and be a more cost-effective option. Both can be installed on a server, personal computer, or in the cloud.