There are diverse types and configurations of secondary storage offered on the market that can make it confusing which one to choose for your needs. The most common question asked is the difference between SSD vs HDD storage, and which one is the best choice for your computer’s secondary storage. In this blog, we will provide you comprehensive insights that compare the difference between SSD vs HDD to help you decide which is best for your industrial computing solution.
The Difference Between SSD vs HDD
The main difference between SSD and HDD is in how they store, write, and access data. Although both are used as the secondary storage of a computer, an SSD is much better in so many ways compared to HDD. Especially for industrial applications, an SSD is the most popular choice for devices that requires durability and reliability when deployed in an extreme environment that may jeopardize mission-critical data.
What Is A Hard Disk Drive (HDD)?
HDD or traditional hard disk drive is a traditional storage device that uses high-rpm spinning metallic disk and a moving head actuator to store, write, and access data. The metal disk is covered by a ferromagnetic coating that can be modified magnetically by the actuator arm to represent individual bits. The disk can spin extremely fast with up to 15,000 rpm during reading, writing, and accessing data. Traditional HDDs rely on mechanical parts such as the mechanical platter (metallic disk) and actuator arm. The mechanical parts of an HDD make it prone to failure when deployed in industrial applications that experience shock and vibrations.
What Is A Solid State (SSD)?
Modern SSD or solid-state drive is the latest storage technology that stores its data in integrated circuits. These integrated circuits are called the NAND flash drives where data is stored, written, and accessed by the devices. SSDs do not have any moving parts, it utilizes NAND (negative-AND) memory chips instead that are physically soldered onto a circuit board. In an SSD there are multiple flash drives where data are stored. SSD read and write speed is extremely fast compared to traditional HDD, just like RAM it uses an electric charge to save data in the flash drives, but the difference is SSD can maintain the charge even if the computer is turned off. This feature provides better performance especially with the sequential read/write operation where it can simultaneously write data across all different flash drives at the same time.
Types Of SSDs: NAND Flash Memory | SLC, MLC, TLC, QLC
There are various types of NAND flash memory that affect the speed, durability, and price of an SSD. Understanding the different types of NAND flash memory may help you to choose the right SSD type based on your needs. The main difference between SLC, MLC, TLC, and QLC is the number of bits inside each memory cells. The name itself is pretty self-explanatory, Single-Level Cell, Multi-Level Cell, Triple-Level Cell, and Quad-Level Cell have 1 bit, 2 bits, 3 bits, and 4 bits per cell.
SLC stands for Single-Level Cell where each cell inside the flash drive only stores one bit. With fewer bits and layers, the memory cells will last much longer with fewer bits getting charged into each cell which, dramatically prolongs the time before the cells wear out. This type of flash drive is the most durable and fastest solid-state drive, best suited for the most mission-critical applications. It also has the longest lifespan between 90,000 – 100,000 P/E cycles (program/erase cycles) and the lowest power consumption. With that said, the SLC SSDs are the most expensive SSD compared to other types of NAND flash technologies.
MLC or Multi-Level Cell has two bits percell on the NAND flash. MLC has a major advantage over SLC NAND due to the lower cost of manufacturing which in turn provides more affordable pricing to end-users. Another key benefit over SLC NAND is the storage capacity on the NAND. Since MLC SSDs store two bits per cell, they offer the same storage capacity as SLC SSDs at half the number of cells. However, an MLC SSD is not as fast as a SLC SSD and will have a lower life span with 10,000 P/E cycles and 20,000 – 30,000 P/E cycles for enterprise-MLC (EMLC). That said, MLC SSDs are good for everyday consumer use like gaming and editing.
TLC stands for Triple-Level Cell, TLC SSDs have 8 charge levels and 2 bits for each cell. A TLC SSD is slower than an MLC SSD but much more affordable in price. . A TLC SSD lifespan is around 3000 – 5000 P/E cycles which fit for normal everyday use in devices like notebooks and tablets. Because the manufacturing cost for producing TLC SSDs is much cheaper compared to SLC and MLC, TLC holds the largest market share for SSDs.
QLC or Quad-Level Cell has 16 levels and 4 bits per cell. QLC is relatively new and has the most affordable price per GB and is often time compared to traditional HDD due to its affordability in pricing. QLC performance is not as good as SLC or MLC but is nearly equal to a TLC SSD; in regards to the overall lifespan, a QLC SSD is only around 1000 P/E cycles. With that said, a QLC SSD is not as robust as SLC or MLC drives but can be an affordable choice if you’re looking for a budget SSD for general applications.
SSD and HDD Storage Protocols | Understanding Your Storage Interface
When it comes to choosing a storage device it is important to understand what interface your storage is running on. The three most common interfaces you will see are SATA, SAS, and NVMe connection interfaces.
SAS or Serial Attached SCSI is a legacy drive interface that is commonly found in large data centers for transferring data to SAS-based external hard drives. SAS is a serial interface where it transfers data from point to point between different devices. The serial interface offers advantages over a parallel interface that is used by its predecessor, the SCSI interface. Moreover, SAS hard drives are typically used in data centers because the drive rotates up to 15K rpm, much faster than SATA drives that typically rotates only up to 7.2K rpm. This makes SAS hard drives much more expensive compared to SATA hard drives.
SATA stands for serial advanced technology attachment or serial ATA, which is a connecting storage protocol that was introduced in 2001. Now the latest SATA interface version is the SATA 3, a SATA 3 SSD with connection speed around 550MB/s read and 520MB/s write speeds or 6Gb per second. Despite having slower rpm compared to SAS hard drive, SATA hard drive has a much larger storage capacity and is more cost-effective. SATA is a pretty common storage interface for connecting SSD to the computer. SATA uses the AHCI command protocol that supports IDE which initially was created for slower spinning disks rather than flash-based memory drives.
NVMe or Non-Volatile Memory Express is built to overcome the speed bottleneck for SSDs that previously existed with the SATA interface which has a bottleneck of 6Gb per second. It is the modern high-performance and optimized storage protocol that compliments the PCIe (peripheral component interconnect express) technology. PCIe SSDs are much faster than the traditional SATA 3 SSD with more channels to transfer data between different devices. PCIe NVMe SSDs are the latest innovation for SSDs because they offer super-fast, low latency, and high bandwidth storage drives that are great for AI edge computing.
SSD vs HDD Form Factors
Due to the hard drive's reliance on spinning platters and actuator arms, its overall form factor is limited in size due to the physics of how small parts can be made. HDD form factors commonly are 3.5”, 2.5”, and 1.8” drives. Where the 3.5” HDDs are commonly used in data centers and 1.8” HDDs are rarely used, most of the HDD drives are the 2.5” size for medium to smaller-scale consumer applications.
SSD, in contrast, has a myriad of form factors that keeps shrinking and evolving as technology advances. Common SSD form factors are the mSATA, 2.5”, M.2, and PCIe AIC (add-in-cards) drives. 2.5” and M.2 are often used in compact devices and industrial systems that required versatile storage expansion with ultra-fast read and write speed. The PCIe AIC is like a GPU card where it's used for applications that require maximum performance of the PCIe lanes. That said, thanks to the NAND flash technology, the SSD form factor can be configured into a variety of shapes and sizes.
How Much Faster Is SSD Compared To HDD?
An SSDs read and write speed is much faster compared to HDD mechanical platters. An SSD drive writes up to 20 times and reads up to 10 times faster than an HDD drive. In addition, the speed gap is expected to widen as computer motherboards start adopting the PCIe 4.0 protocol. Thanks to the NVMe interface, PCIe SSDs can surpass the SATA interface bottleneck at 6Gb per second, providing a huge performance increase in the read and write speeds.
SSD vs HDD: Durability And Reliability
A hard drive’s spinning platter and mechanical arm is the weakest link and has a high risk of failure, especially when exposed to shock and vibrations. An HDD spinning platter can spin up to 15K rpm and a tiny jitter can easily corrupt the data and cause permanent damage to the internal drive. This is why it is highly recommended to use an SSD instead of an HDD for industrial deployments. Since SSDs do not have any moving parts, they are great storage options for applications that experience shock and vibration. In addition to kinetic movement, some high-end SSDs are even tested for wide temperatures. SSDs are one of the major factors that enable industrial computers to comply with the MIL-STD-810G standard for shock and vibration resistance.
How Long Is The Lifespan Of SSD vs HDD?
In the early days of SSD drives, they were known to have a short life span, however, this is not an issue for modern-day SSDs. Early iterations of SSDs had shorter life spans due to the continuous electrical charge in the flash drive’s cell which, is known as “cell death”. However, modern SSDs have around 3,000 write cycles with enterprise drives featuring even more. A key benefit from modern SSDs is their ability to monitor read/write levels across all cells; this feature helps increase the longevity of the drive to ensure optimization of performance. Moreover, modern SSDs are capable of operating bad block management where it has a spare cell to replace the death of a cell, this means that the storage size and lifespan of SSD are positively correlated.
The HDD lifespan, on the contrary, is not highly affected by the number of times it writes data onto the platter and has years before it eventually fails. Even so, hard disk drives also face the challenge of file fragmentation where data is scattered throughout the platter from the constant rewriting of data that was not written sequentially. As a result, it takes more time for the drives to access the file. For this reason, HDDs need to be defragmented regularly.
Capacity Difference Between SSDs vs HDDs
Newer and faster SSDs usually have less storage space compared to HDDs. NVMe SSDs generally only have a capacity range up to 2TBs, with enterprise drives climbing into the 8TBs of storage capacity. HDDs range from 5TB to even 18TB on the high-end of the HDD storage spectrum. HDDs with huge storage space are commonly used for severs or NAS devices.
Price Difference Between SSD vs HDD
SSD cost per GB is still much more expensive compared to the traditional HDD drives. The more compact, faster, and larger the SSD speed and storage is, the more expensive it becomes. The price per GB of SSD can easily double the price of HDD, and for higher-end SSDs it can cost triple or more compared to HDD. Despite that, SSD’s speed, durability, and reliability are absolutely worth it to prevent downtime for mission-critical applications. The type of storage media and performance requirement depends on the application. Both SSDs and HDDs still have their place in the storage media world but as the cost of NAND flash continues to decrease, SSDs will eventually overtake HDDs in terms of overall performance.
SSD or HDD | Which Storage Solution To Choose?
It is easy to see how the performance and technology behind SSDs are much more beneficial in comparison to HDDs However, it’s important to understand your needs to decide which storage is best for you. For tough and complex industrial applications, SSDs are the right choice because it’s extremely fast, durable, and reliable. SSDs are often deployed with industrial computers that are required to withstand extreme environments, especially for applications that experience shock and vibration. Lastly, if you only need to back up large amounts of data in a controlled environment, an HDD may be the better choice because of the cost, capacity, and lifespan compared to an SSD.
Where To Get The Best Storage Solution For My Industrial Applications?
All things considered, choosing the right storage solution for your industrial applications can be pretty complicated. Here at Premio, we provide engineering experts to help you choose the right technologies for the best of your industrial applications. With 30 years of experience in designing and manufacturing industrial edge computing solutions for enterprises' complex and highly specialized industrial applications, we are confident to help you transform your businesses. If you are looking for rugged industrial solutions for your applications, we encourage you to reach us from the Contact Us tab to get insights from our brightest experts at Premio.