SSD the big name in internal storage solutions for consumer storage. Its advantages over hard drives are so important that its use has been standardized in all types of equipment, whether portable or desktops where at least the main unit is based on solid storage. If its use by manufacturers in new equipment is massive, the same can be said for renovations, where a solid state unit is one of the best hardware updates that a user can perform to improve old equipment. Whether replacing the hard drive in a laptop or installing an SSD (alone or next to them) in a desktop computer, the benefits are tangible from the first minute in the performance section, but also in its lower noise, heat emission or consumption , derived from its base in NAND flash memories and the absence of moving parts.
The improvement of its robustness and resistance to failures in the past generations; the arrival of new smaller and faster formats and a constant drop in prices has added additional attractions to make SSDs the great standard for mass storage. The sales of hard drives for internal storage to fall by 50% by 2020. A clear sign of the popularity of SSD, while hard drives still have a life ahead in the business market (servers and data centers) and in the Consumption thinking of external storage, be it a NAS or an external disk, where we can take advantage of the units that we replace by the SSD. Today we update our SSD Guide with the latest quarterly news and a selection of current models and their prices, reviewing their operation, formats, interfaces and everything a user should know about this type of units.
How an SSD works
To understand why these units are so useful, it is convenient to understand how the memory architecture of a computer works and each of its parts: the cache, the RAM memory, and the mass storage unit. The cache memory is the most internal memory unit, while the RAM is the middle point. The storage unit is where all the rest of the data that needs persistence is stored and it stores the data of the operating system, applications, games, configuration files and all the user files, documents, video or music.
There is a big difference in performance between the three. The cache memory is very fast but of low capacity. RAM also operates at nanosecond speeds, but it is very expensive and its capacity is limited. In front of them, a traditional hard drive works at millisecond speeds. As a result, the storage system has been a great bottleneck for the performance of the entire PC. And this is where the SSDs come in, much faster, which significantly reduces the loading time of programs and processes, making your computer feel much faster.
SSDs or “solid-state drives” have the same purpose as a hard disk: store data and files for long-term use. The difference is that modern SSD (since 2010) use a type of flash memory (similar to those used in RAM) but unlike them are based on NAND doors that do not erase the data each time the computer is turned off. The data in an SSD persists even when it has no power. Being non-volatile memories, they do not require any kind of constant power or batteries to avoid losing stored data, even in sudden power failures. In front of a typical hard disk with magnetic plates, turntables and a reading needle, the structure of an SSD changes completely. It has no mechanical or moving parts and uses a system of electric cells to send and receive data quickly. With this, and in addition to other advantages, even the lowest performing SSD triples the data transfer performance offered by a hard drive.
The most popular and versatile format is the one that uses the same standards as hard drives, 2.5 inches. If you are going to mount it on a laptop you have to make sure that its height is supported, because there are units of 9.5 mm and 7 mm thick. For desktop computers, all existing ones are served to you. You can use them as they are delivered although the ideal is to buy a 3.5-inch adapter for better mounting on a PC tower.
The second most important format to value is the so-called M.2, with advantages in size, weight and consumption over those that use the standard 2.5-3.5 inches with dimensions of 80 x 22 and 3.5 mm. A variant of it is mSATA, even smaller with dimensions of 50.8 mm x 29.85 mm x 4.5 mm, but less supported. Among its disadvantages, we can mention a slightly higher cost and less versatility since not all motherboards support it. The section of the performance is identical to the previous ones if they use SATA, although it is much superior when using PCIe as we will see later. It is the format that is being imposed and the one recommended to be used on new boards that support it. A third format that can be found for desktops is the card type punctured directly into a PCI slot on the motherboard. This format includes the units that mount their chips directly on the card or if it is used as accessories to mount the previous M.2 on plates that do not have a specialized connector.
Another distinctive element when buying an SSD is the connection bus to which they connect. The 2.5-3.5 inch units connect to the SATA interface (do not buy anything that does not support SATA-III – 6 Gbps), while M.2 can connect to both SATA and PCIe. The latter is the most widespread and those that make the difference in performance. However, not all SSDs offer the same performance even under the same connection bus, derived from the memories used and especially from its controller. The user who purchases an SSD today, should not settle for less than one unit that does not reach 500 Mbytes per second on SATA in data transfer speeds in both reading and writing. There are very cheap SSDs that reduce this data, especially in writing. Avoid them, they are not worth it.
The M.2 that use PCIe are the fastest units that you will find in solid storage of consumption. They use the native PCI-e interface to trigger their performance up to a theoretical maximum that comes to multiply by five the solid-state drives connected to SATA and fifteen that of hard drives. Although in the beginning, its price was prohibitive for the big consumption, the distances in front of SATA have been reduced enormously as you will see at the end in the purchase guide of SSD. If you can afford it, do not hesitate, the future of PC storage passes through them.
It is also worth knowing that the new generations of M.2 PCIe SSD support the NVM Express standard, designed from scratch, taking advantage of the low latency and parallelism of PCI Express SSDs, offering spectacular performance and making the unit bootable, allowing to completely dispense other storage units. If you are going to buy this type of SSD to completely replace the hard drive, make sure that your board supports or can be updated to support the NVM protocol and turn the unit into bootable. Otherwise, you can not use it as the main unit to install the operating system, although it can be used for data storage.
SSD storage capacity
There is an important difference between the way data is handled by an SSD and an HDD. An SSD writes data into chunks called “pages”. A group of pages is called a block and in order to write new data in a busy block, the whole block has to be deleted first. To avoid data loss, all information that exists in the block must first be moved to another location before the block can be deleted. Once the data is moved and the block is deleted, only then can it be written. This process is almost instantaneous but requires empty free space to work properly. If there is not enough free space, the process loses efficiency and slows down. We discuss this technical section because it affects the capacity when we buy an SSD. To achieve maximum efficiency we should leave approximately 20 percent of the unit free.
That is why -actually- we recommend the purchase of a unit of at least 250 Gbytes if we want to install it on a laptop to replace the installed hard disk. We would avoid the units of 128 and 64 Gbytes, except if the budget is critical or if the laptop has double installation space and we want to combine the SSD with a hard disk. Or a PCIe M.2 SSD and a SATA SSD, something that is possible in many laptops and in all new desktops. In a desktop PC, the storage capacity needs are greater both if we replace all the hard drives (expensive but more effective) and if we make the SSD coexist (as the first boot unit for the system and applications) with the hard drives installed. The possibilities are very broad.
To mount an SSD of low capacity and price that works next to the hard disk is a good option not to spend too much. If your budget is wider and you want the best, you can bet totally for SSD. Units with 1, 2 and 4 Tbytes are already common; Fixstars has models with 6 Tbytes for sale; SanDisk or Samsung will market units of 8 Tbytes this year, the same as Intel in the hands of Micron will offer models with 10 Tbytes.
How long is an SSD?
Despite its mechanical components, hard drives remain “standard and signal” in terms of storage unit strength and hence its massive use in data centers 24/7 where reliability prevails above all else. In addition, they require tests and certifications that can last for months and therefore the entry of SSDs has been up to now quite shy. Unlike hard drives, SSDs have no moving parts, which gives them a great advantage in terms of mechanical failure. In contrast, SSDs are more prone to power failures while the unit is running, causing data corruption or even total failure of the devices. In addition, the memory blocks in an SSD have a limited number of write operations.
Fortunately, the new generations have improved a lot in reliability. All SSDs include free additional memory cells for when the others fail not to lose capacity, reallocating damaged sectors. Endurance tests have confirmed this increase in reliability with some series of surviving units after supporting a massive writing test above 2 petabytes. A huge amount of data that a user in real conditions (normal use) would take tens of years to complete
Yes, it should be noted that in the latest generations of SSD, manufacturers are betting on NAND TLC flash memory, triple level per cell, and QLC or quad-core per cell will be the following. This technology increases the density of storage and reduces costs, but reduces the resistance of previous formats such as MLC and especially SLC, Single-Layer Cell, which only stores one bit per cell and that you will no longer see in the consumer market. To compensate, the best manufacturers have increased the warranty up to 5 years in units of consumption, while there are professional models with up to 10 years of warranty. The official half-life of an SSD is estimated between 5 and 7 years.
SSD Guide May 2019 – News
Any of the major manufacturers (Samsung, Kingston, OCZ-Toshiba, SanDisk-WD, Crucial, Seagate …) will offer us interesting models, varied in formats, performance and capacity. And, the good news continues regarding its cost, at cheaper prices than in the month of January where we updated this guide for the last time because the price of SSD has fallen to historical levels: around 10 cents / GB and lower. In fact, it is expected that the price of SSD will continue to fall in 2019, especially in PCIe formats. From there, the news has been interesting. Highlight: