Greetings, Dear friends! At choosing SSD drive for a computer (you can learn more about this) in the characteristics you will find Various types memory. There are not so many of them, but they still differ in parameters.

Today we'll talk about what type of memory is best for SSD and what you should pay attention to first of all. Let's start?

Existing options

Almost any solid state drive today is NAND-based. Depending on the features, they are divided into three types:

• SLC is single-level. Each cell remembers one bit depending on the state - it can be turned on or off. Has the lowest power consumption, the highest rewriting speed and the number of its cycles. However, it is expensive, so it is used mainly in cool server solutions.
• MLC is multi-level. The cell stores two bits. It is cheaper, as the characteristics are "simpler". Used primarily on workstations and mid-range servers.
• TLC is three-tiered. The cell stores three bits. It has the highest density, is less hardy and works relatively slower. The most affordable type, therefore, is widely used in solid-state drives designed for mass consumption.

These types are of the planar type, that is, they are "flat". Them common disadvantage the fact that to increase the density it is necessary to reduce the technical process, and it is impossible to do this indefinitely for physical reasons.

3D cells are devoid of these drawbacks. Cylinder-shaped. They are called 3D V ‐ NAND or 3D TLC. The technical characteristics correspond to the planar TLC memory type.

Manufacturers

There are fewer companies that make chips for solid state drives than there are brands that make SSDs.
In 2017, the production was carried out by:

• Intel / Micron;
• Toshiba / SanDisk;
• Hynix;
• Samsung.

It is no coincidence that the first two items contain two companies through a slash - these brands have established joint production and label products in approximately equal proportions.

All brands that produce SSDs buy chips from these companies, so at different brands essentially the same storage devices are installed. There are no fundamental differences between the brands of memory: they are produced according to a single technological process and cost approximately the same.

The price is already influenced by transportation costs: buying a drive with memory made in Singapore in 2018 will cost less than with memory made in the USA, given that the cost of chips and controllers is also approximately the same.

Which one to give preference

Having studied any performance table, it is easy to make a choice:

• TLC or MLC - the latter is more reliable and faster;
• MLC or 3D NAND - the latter is slower and designed for fewer rewriting cycles;
• TLC or MLC 3D V-NAND - as mentioned above, in terms of technical parameters, single-level memory is better.

Since solid state drives are bought primarily for the sake of increasing computer performance, more fast loading operating system and games, it is logical that it is preferable to use single-level memory. However, everything depends on the price: as I noted, such a pleasure will cost a lot.
Is it rational to overpay if you are upgrading or assembling, albeit a fancy, but still an ordinary home computer? Definitely not.

Therefore, TLC is exactly the type of cells that you should be guided by when choosing a solid state drive. By the way, in this case, the publication "" will be useful to you. Although this memory is slow compared to other types, it is significantly faster than normal memory. HDD.

About manufacturers hard drives and which brand to give preference to, you can.

And as a possible purchase, I can recommend the device Kingston SSDNow A400 240GB 2.5 ″ SATAIII TLC (SA400S37 / 240G), which has very good parameters for reasonable price, but you can buy in this popular online store.

Thank you for your attention and see you in the following publications. Share this article with your friends at in social networks and don’t forget the newsletter!

When choosing external memory for home computer, users often wonder which is better - MLC or TLC, parameters specified in the characteristics of the drive.

External SSDs have become a familiar addition to almost any computer, as they are convenient to use, easily connect to USB inputs, store a huge amount of information and are compact in size. Few of the users to expand the amount of memory buys an additional magnetic disk, since it is much more expensive than the external one, and you will be tortured to connect it.

Therefore, more frequent problem becomes the choice among the SSD drives offered on the market. In this case, they pay attention to the MLC and TLC parameters, which significantly affect the price.

It should be noted that sometimes you can find another parameter - SLC. Discs with technical characteristics such a parameter is specified, they are much more expensive and are less common, since usually users are looking for large drives at a low price. So, the mysterious designations of the parameters denote only the number of bits stored in one memory cell of the drive:

• SLC - Single Levell Cell - 1 bit of information in a cell;
• MLC - Multi Level Cell - 2 bits per cell;
• TLC - Triple Level Cell - 3 bits.

It is clear that the information density in TLC disks is higher than in MLC or SLC, therefore, this parameter is more common among the most voluminous drives. Why is TLC cheaper than MLC among drives with the same memory? The point is that the recording density is not the most important parameter of a disc's quality. The speed of writing and erasing information and the number of write cycles are also important.

MLC drives have approximately 50% faster erasure times than TLCs, and have three times the rewrite cycles. More better parameters for disks with old technology SLC. They have 3 times less erasure time than TLC and 100 times more cycles. However, the cost of manufacturing 1 GB of memory using TLC technology is much lower than that of MLC and SLC technologies.

Therefore, before deciding which is better, TLC or MLC, you should understand for yourself why you are buying external memory.

If the disk will store important information, which is also often overwritten, it is better to choose more expensive MLC disks... If you just need a large amount of external memory, say, for an archive of music or movies, then you can buy a larger and cheaper TLC disk that will last 5-6 years with fairly frequent rewriting.

The number of rewriting cycles for TLC disks is, on average, about 1000. For MLC, this figure reaches 3000, so its reliability with frequent use is higher. For the most important tasks and information, traditional magnetic hard disks HDDs that even fail gradually rather than suddenly. That is why HDDs are used as system drives. But their cost is quite high.

Below is a table of popular models of TLC and MLC drives with comparative characteristics and prices:

Drive brand	Volume, GB	Memory type	Reading speed	Price, rub
KINGSTON SMS200S3			77000	1 890
A-DATA 550 ASP550SS3-120GM			60000	2 990
CORSAIR Force LE CSSD-F480GBLEB			83000	8 890
Transcend 500 SATA SLC			85000	40 701

3D NAND MLC and TLC Bulk Memory

New technologies make it possible to increase the density of memory cells in a single die and make SSD drives more capacious. An example of such new products is 3D NAND technology, which has already been implemented by some manufacturers.

Although the first volumetric chips were of the TLC type, they are currently being produced. The volumetric arrangement of the cells allows you to increase the speed, but you need to understand that in 3D NAND, only 2 bits of information are still stored in one MLC cell, that is, in this respect, it does not differ from the previous structure.

The main advantage of the new 3D NAND drives is a higher cell density, which means a more compact size. In many situations, this advantage is key, even if the reliability and rewrite cycles are less than those of SLC drives.

The cost of three-dimensional SSD drives is still slightly higher than that of two-dimensional ones with comparable capacities:

Drive brand	Volume, GB	Memory type	Write speed, MB / sec	Price, rub
Samsung 850 PRO	256	MLC 3D NAND	520	8 499
Samsung 850 EVO	250	TLC 3D NAND	520	6 499
Goodram CL100	240	TLC	400	5 490
SiliconPower Slim S60	240	MLC	300	5790

This is due to the limited number of manufacturers capable of using NAND technology. However, over time, the price of bulk SSDs is unlikely to be very different, since such production allows significant savings in raw materials, although it requires significant initial costs.

Depends on what your computer is for. If you just want the system to start and run faster, 64 GB is sufficient. To speed up the programs that you use every day, you need 128 or 256 GB drives. Anything more is for video editors and avid gamers.

See how much space is taken up by the programs you use every day. Add the system size to these (usually 20-30 GB). This will tell you how much memory you need. There is no need to put everything on the SSD. Photos, videos and infrequently used programs can be stored on a regular HDD.

It is better not to fill inexpensive SSDs to the eyeballs - the more they are clogged, the slower they work and the faster they wear out.
Choose memory with a surplus so the drive will run longer and faster.

Memory type: TLC or MLC?

A common myth is that SSDs fail quickly. In fact, the manufacturers have foreseen everything. Data writing to disk is optimized: the same cells will not be constantly used. In case, over time, a certain amount of memory is "overwritten" by constant recording of files, there are several spare gigabytes.

Of course, if you fill the SSD to capacity every day, delete all data from it and clog it again, it will quickly fail. But with real use, no more than 20 GB is usually recorded per day - in this mode, the rewriting cycles will not end in the foreseeable future.

SSDs can be equipped with two types of memory: TLC and MLC. TLC memory is getting cheap SSDs, they are rated for about 1,000 rewrite cycles. TLC disks should only be used to install the operating system and basic programs... For more active use it is better to buy a disk with MLC memory. Its resource is 3,000-5,000 cycles.
MLC is the preferred option: disks with MLC are not much more expensive, but they can be actively used for a long time: they will definitely work for 10 years, most likely even longer.

I also heard about eMLC and SLC

TLC and MLC are not the only memory types in SSDs, they are just the most common. EMLC memory can handle more write cycles than regular MLC. It is intended for corporate purposes, the letter "e" in the name is an abbreviation for the English Enterprise.

SLC is the longest-lasting and most expensive type of memory, and can support up to 100,000 write cycles. For the average user, buying an SSD with SLC memory is pointless.
Choose between TLC and MLC. Leave eMLC and SLC to the enterprises that build servers on their basis.

What interface should I connect to?

SSDs are usually connected to computers and laptops via SATA interface... It comes in three generations: SATA, SATA II and SATA III. It all depends on how modern your computer is. Your best bet is to connect your SSD to SATA III with a maximum read / write speed of 600MB / s. The average SSD runs at 450MB / s, so it can push it to its limits.

It makes no sense to connect an SSD to a regular SATA, it throughput no higher than HDD. An SSD won't even come close to running at its optimal speed.

The maximum read / write speed of SATA II is 300 MB / s. That is, the SSD will not be able to work at full speed, but the difference with the HDD will still be noticeable. If it is not possible to install an SSD via SATA III, SATA II can be used.
SATA III is desirable, SATA II is acceptable, SATA is meaningless.

Also, SSD drives are available with support for the PCI-Express (PCI-E) interface. This connector in computers is usually used to connect a video card. Its speed is much higher - some SSDs "overclock" up to 2 GB / s, usually up to 800 MB / s .. But such parameters are needed only for servers and in a regular computer will not give you anything.
Don't chase PCI-E.

I need a compact SSD

If a standard 2.5-inch hard drive is too large for your computer, look towards M.2 SSDs. Make sure that this connector is on the motherboard first.

M.2-SSDs support both SATA III and PCI-E, so there won't be any speed issues. Such hard drives are, of course, more expensive - it is logical that one has to pay for compactness.

But the most important thing is the controller?

The write speed of the SSD depends on the controller. Many people say that deciding on a controller is the most difficult and important thing when choosing solid state drive... In fact, in 2017, all controllers provide normal speed. In benchmarks, the difference will be visible, but in real use, all SSDs perform approximately the same.

Even cheap controllers deliver 400 MB / s for reading and 200 MB / s for writing. Expensive SSDs with more advanced controllers have faster speeds, but you won't feel the difference. But the difference in price is very even.

To write to disk at the maximum speed, you also need a source of files that can provide this speed. Rare flash drives and external hard drives deliver more than 150 MB / s.

“Whatever one may say, it is very problematic to rest on the speed of recording, and therefore you should not worry about it categorically,” - Sergey Vilianov, IT journalist, former editor of “Computerra” magazine, analyst of the 3DNews portal.

Briefly

1. 64 GB for the system only, 128 GB for the system and programs, 256 GB is enough for almost everything.
2. When buying an SSD with TLC memory, be prepared to change it in 5-7 years. MLC will live longer. EMLC and SLC discs are very expensive and made for enterprises.
3. Ideal is to connect the SSD to SATA III. Acceptable - to SATA II.
4. If you need a compact SSD, choose from the M.2 models.
5. Don't bother with the controller.

And most importantly, don't even think about whether to switch from HDD to SSD. Of course it's worth it! After that, you simply cannot take seriously computers in which the system is installed on a regular hard drive - so much is the speed advantage of SSD.

In the first quarter of 2016, HDD sales hit a ten-year low. Sales will continue to decline, because the future belongs to SSDs.

MLC 3D NAND is the next stage in the development of solid state drives. Advantages and prospects of this technology for the near future.

SSDs are known to be produced for household use, mainly of two types: MLC and TLC. Judging which is better - MLC or TLC - does not make much sense, since each type has its own advantages and disadvantages.

Recently, the technology of three-dimensional cell formation - 3D NAND - has begun to be used in the production of solid-state memory. This allows us to overcome the main problem - the limitation of the crystal dimensions in length and width. With a three-dimensional arrangement, the layers of cells are superimposed on one another and their density increases significantly.

This also increases the amount of memory that can be placed in one crystal. Moreover, the speed of information transfer between cells also increases, since they are more densely located. However, things are not so simple.

NAND technology grows layers of cells on a substrate by vapor deposition of semiconductors. Cell addresses are obtained exactly at the intersection of bit lines and lines from cells. That is, such a crystal looks like a waffle. In 3D NAND technology, it is also necessary to interconnect vertical layers. For this, after the layer has grown, the holes are etched through which the layers are connected to each other.

These holes must be very precisely located, strictly vertical, without deviating or twisting anywhere. Currently, there are restrictions on the number of layers that can be etched with modern machines. The ratio of the vertical channel height to its width is still from 30: 1 to 40: 1. Therefore, the number of layers that can be stacked on top of each other and the vertical holes etched into them is 32 or 48.

Etching holes with a ratio of 60: 1 will require new machines, but only this will allow the creation of 3D NAND memory chips with 64 layers of cells.

3D MLC - what's next

The first drives based on 3D NAND technology were made of the TLC type. This is understandable, since 3 bits of memory can be stored in one TLC cell, so the dimensions of such a die are simpler from the point of view of manufacturing.

But soon the first 3D MLC NAND drives appeared, which stored only 2 bits in one cell and made it possible to speed up work and increase reliability. By the way, 3D MLC 3D memory consumes less power, so its application will only expand.

Further development three-dimensional technology 3D NAND of the MLC type will go in two ways:

• increasing the number of layers;
• stacking 2 or more 3D matrices into one structure.

The first path requires the creation of new machines for ultra-precise etching of vertical channels with a length to width ratio of 60: 1, 100: 1, or 120: 1.

The second path is already being used to create 96-layer MLC 3D NAND chips by connecting two 48-layer dies. This method is called string technology and, in principle, allows you to connect more than 2 matrices. But so far the cost of such drives does not justify the investment in their production.

I recommend purchasing an SSD drive with an optimal speed / reliability ratio of MLC or 3D NAND memory. Read / write speed closer to 500/500 MB / s is considered high enough. The minimum recommended speed for more budget SSDs is 450/300 MB / s.

The best brands are: Intel, Samsung, Crucial and SanDisk. As more budget option can be considered: Plextor, Corsair and A-DATA. Problematic models are more common among other manufacturers.

For a worker or multimedia computer(video, simple games), a 120-128 GB SSD will suffice, and here A-Data Ultimate SU900 on MLC memory will be an excellent choice.
SSD A-Data Ultimate SU900 128GB

For gaming computer the middle class needs a volume of at least 240-256 GB, an SSD from the A-Data Ultimate SU900 or Samsung 860 EVO series is also suitable.
SSD A-Data Ultimate SU900 256GB

SSD Samsung MZ-76E250BW

For a professional or powerful gaming computer, it is better to take a 480-512 GB SSD, for example Samsung SSD 860 EVO.
SSD Samsung MZ-76E500BW

For computers and laptops with an M.2 connector, a super-fast SSD (1500-3000 MB / s) in the appropriate format would be a good option.
SSD Samsung MZ-V7E500BW

When choosing a volume, you are guided by your needs, but you should not neglect them for the sake of higher speed. If you doubt the correctness of your choice, we recommend reading reviews of specific models.

2. What is the difference between expensive and cheap SSD

Inexperienced users may be confused about why SSD drives of the same size, with the same declared speed characteristics, differ so much in price, sometimes several times.

The fact is that different SSD drives can use different types memory, which, in addition to speed indicators, also affects reliability and durability. In addition, memory chips from different manufacturers also differ in quality. Naturally, the cheapest memory chips are installed in cheap SSDs.

In addition to memory chips, an SSD disk has a so-called controller. This is a microcircuit that controls the processes of reading / writing data to memory chips. Controllers are also produced by different companies and they can be both budgetary with lower speed and reliability, and higher quality. Cheap SSDs, as you know, also have the worst controllers.

Many modern SSDs use fast DDR3 memory as a clipboard to further improve performance, the same as RAM computer. Most budget SSDs may not have a clipboard, making them marginally cheaper but significantly slower.

But that's not all, it even comes down to saving on such important components of an SSD drive as capacitors, which are necessary to prevent integrity violations and data loss. In the event of a sudden power outage, the electrical energy stored in the capacitors is used to complete the recording from the clipboard to the memory chips. Unfortunately, not all even high-quality SSDs are equipped with backup capacitors.

The layout itself and the quality of the desoldering printed circuit board are just as different. More expensive models have more sophisticated circuitry, quality element base and desoldering. The engineering solutions for the lowest-cost SSDs are based on outdated circuits and leave much to be desired. The defect rate in cheap SSDs is also higher, due to assembly in cheaper factories and more. low level production control.

And of course the price depends on the brand, the more famous it is, the more expensive the SSD is. Hence, there is an opinion that you should not overpay for the brand. But the fact is that often it is the brand name that determines the quality of an SSD drive. Most well-known manufacturers who value their reputation will not allow themselves to produce low-quality products. However, there are exceptions here, in the form of well-known and popular brands, which, nevertheless, should not be recommended for purchase.

The main differences between SSDs, which you need to focus on, we will briefly understand in this article and you can easily choose the model that suits you.

3. VolumeSSDdisk

Volume is the most important parameter of an SSD drive.

If you only need an SSD for acceleration Windows boot, office programs and increasing the responsiveness of the system, then, in principle, a volume of 60-64 GB (gigabyte) will be enough.

If you want to speed up the work of serious professional applications (video editing, design systems, etc.), then you need a 120-128 GB SSD drive.

For a gaming computer, it is advisable to purchase an SSD with a volume of at least 240-256 GB, since modern games take up a lot of space (30-60 GB each).

In the future, focus on your needs (how much space is needed for your programs, games, etc.) and financial opportunities... It is not advisable to use an SSD for data storage, for this you need a more capacious and cheaper hard disk drive (HDD) with a volume of 1-4 TB (1000-4000 GB).

4. SSD read / write speed

The main indicators of SSD drive speed are read speed, write speed and access time.

According to statistics, the number of read operations per conventional computers users are 20 times more than the number of write operations. Therefore, reading speed is a much more important characteristic for us.

The read speed of most modern SSDs is in the range of 450-550 MB / s (megabytes per second). The higher this value, the better, but 450 MB / s is, in principle, quite enough, and taking an SSD with a lower read speed is impractical, since the price difference will be insignificant. But do not blindly trust the representatives of budget brands, as the speed of cheap SSDs can significantly drop as the disk space fills up. The speed of a particular SSD disk model in real conditions can be found out from tests on the Internet.

The write speed of most SSDs is in the 350-550 MB / s range. Again, the faster the better, this is understandable. But due to the fact that write operations are performed 20 times less frequently than read operations, this indicator is not so critical and the difference will not be very noticeable for most users. But the price of discs with more high speed records will be noticeably higher. Therefore, 350 MB / s can be taken as the minimum record speed. Purchasing an SSD with an even lower write speed will not bring significant savings, so it is impractical. Please note that some manufacturers indicate write speed for the entire line SSD drives, in which there are different volumes. For example, Transcend's SSD370S line has drives ranging from 32GB to 1024GB. The write speed for the entire line is indicated at 460 Mb / s. But in fact, only 512 and 1024 GB models have this speed. The photo below shows a fragment of the Transcend SSD370S package with a capacity of 256 GB with a real write speed of 370 MB / s.

The access time determines how fast the disk finds the required file after receiving a request from a program or operating system. For conventional hard drives, this figure is in the range of 10-19 ms (milliseconds) and significantly affects the responsiveness of the system and the speed of copying small files. SSD drives, due to the absence of moving parts, have access speeds up to 100 times higher. Therefore, this parameter is usually not focused on, any SSD provides an incredibly high access speed. Nevertheless, higher quality models can have access times of the order of 0.1 ms, and the most budgetary ones can have 0.4 ms. The difference in access time by 4 times speaks not in favor of budget SSDs. With this parameter, manufacturers of budget SSDs can also be cunning and indicate the theoretical value under ideal conditions.

You can find out the real speed characteristics of SSD drives from tests on the most reputable technical portals. You can download a file with links to them at the end of the article in the "" section.

5. Types of memory and SSD resource

Modern SSD drives use several types of memory - MLC, TLC and 3D NAND (V-NAND).

MLC is the most popular type of memory for SSD drives with an optimal price / speed / durability ratio and an estimated resource of 3000-5000 rewriting cycles.

TLC is a cheaper type of memory found in budget SSDs, with a rewrite resource of about 1000 cycles.

3D NAND is a modern fast memory developed by Samsung with the highest rewriting capacity. Fits into more expensive Samsung SSD models.

There is a myth that SSD drives wear out very quickly. Therefore, you need to choose models with the maximum possible resource and use all sorts of tricks in the operating system settings to extend the service life of the SSD disk, otherwise it will quickly work out its resource and fail.

In fact, the resource of modern SSDs matters only when they are installed in servers where the disks are running to wear and tear around the clock. In such conditions, due to the colossal number of rewriting cycles, SSDs really serve an order of magnitude less than their older brothers - mechanical hard drives. But we already know that in computers of ordinary users the number of write operations, due to which wear and tear occurs, is 20 times lower than read operations. Therefore, even with a relatively heavy load, the resource of any modern SSD will allow it to work for 10 or more years.

Despite the fact that the data on fast wear is highly exaggerated, it is not worth buying an SSD based on the cheapest TLC memory, as the savings will be insignificant. Today the most the best option there will be an SSD disk with MLC memory. And the actual lifespan of an SSD disk will depend more on the quality of production and. Pay more attention to the brand and the warranty period.

6. Clipboard

The clipboard (cache) based on DDR3 memory speeds up the performance of the SSD disk, but makes it somewhat more expensive. For every 1 GB of SSD space, there must be 1 MB of DDR3 cache. Thus, an SSD with a volume of 120-128 GB must have 128 MB DDR3, 240-256 GB - 256 MB DDR3, 500-512 GB - 512 MB DDR3, 960-1024 GB - 1024 MB DDR3.

Some models have older DDR2 memory caches, but this does not significantly affect performance.

7. Protection against de-energizing

It is desirable that a disk with DDR3 cache has Power Protection, which is usually based on tantalum capacitors and allows data from the buffer to be saved to memory chips in the event of a power outage of the SSD. But if you have a source uninterruptible power supply(UPS, UPS), the power failure protection is negligible.

SSDs without a DDR3 memory cache do not require additional protection against power outages.

8. SSD controllers

There are many controllers for SSD drives. The most popular brands include Intel, Samsung, Marvell, SandForce, Phison, JMicron, Silicon Motion, Indilinx (OCZ, Toshiba).

The best SSD drives are built on Intel, Samsung, Marvell controllers. In the middle class, the more popular SandForce controllers and the younger Phison controllers are more popular. Inexpensive SSD models are often content with older budget JMicron controllers and younger Silicon Motion controllers. Indilinx made fairly reliable controllers and was bought out by OCZ and then Toshiba for use in their mid-range SSDs.

But each manufacturer has both cheaper and more expensive controllers. Therefore, you need to navigate by specific model controller, an overview of which is easy to find on the Internet.

Most of the controllers in entry-level and mid-range SSDs are 4-channel. Top SSD models are equipped with faster and more modern 8-channel controllers. But don't bother too much with controller models, it's not always easy to figure it out. Focus primarily on the brand, the declared characteristics of the SSD drive and real tests of a specific model, which often also consider the advantages and disadvantages of the installed controller and other electronic filling of the SSD.

In addition to the read / write speed, the controller also depends on the support of various technologies designed to improve the operation of the SSD disk.

9. Supported technologies and TRIM function

An SSD drive, depending on the model and the controller installed in it, can support various technologies designed to improve its performance. Many manufacturers design their proprietary technologies to deliver more marketing value than actual value to users. I will not list them, this information is in the descriptions of specific models.

The most important feature that any modern SSD should support is TRIM (garbage collection). Her job is as follows. An SSD can only write data to free memory locations. As long as there are enough free cells, the SSD disk writes data to them. As soon as there are few free cells, the SSD needs to clear cells, data from which are no longer needed (the file has been deleted). An SSD without TRIM support clears these cells just before new data is written, which significantly increases the write operation time. It turns out that as the disk fills up, the write speed degrades. An SSD with TRIM support, having received a notification from the operating system about the deletion of data, also marks the cells in which they were unused, but clears them not before writing new data, but in advance in free time (when the disk is not used very actively). This is called garbage collection. As a result, the write speed is always kept at the highest possible level.

10. SSD hidden area

Each SSD has a fairly large amount of memory in a hidden (inaccessible to the user) area. These cells are used instead of failing ones, due to which the volume of the disk is not lost over time and the safety of data is provided, which is previously transferred by the disk from the “sick” cells to the “healthy” ones.

In high-quality SSDs, this hidden volume can reach 30% of the declared disk size. Some manufacturers, in order to save money and gain a competitive advantage, make the hidden disk volume less (up to 10%), and user accessible more. Thanks to this, the user gets more available volume for the same money.

But there is another negative side to this manufacturer's trick. The fact is that the hidden area is used not only as an inviolable reserve, but also for the TRIM function. Too small amount of the hidden area leads to insufficient memory required for background data transfer (garbage cleaning) and the speed of the SSD disk with high occupancy (80-90%) degrades greatly, sometimes several times. This is the price of the "free" additional volume and that is why high-quality SSD drives have a large hidden area.

The TRIM function must be supported by the operating system. All versions starting from Windows 7 support the TRIM function.

11. SSD manufacturers

The best manufacturer of SSD drives is Intel, but their cost is very high and they are used mainly in the corporate sector for mission-critical systems and servers.

The next leader in terms of technology is Samsung. Their SSDs cost on average higher than all the others, but they are of impeccable quality, reliability and speed.

The best in terms of price / quality ratio were recognized SSD brands Crucial, Plextor ( trademark Samsung) and SanDisk.

Also, as a compromise option in terms of price / quality, you can consider the SSD of the proven Corsair brand and A-DATA.

I do not recommend purchasing SSDs sold under the Kingston brand, as most of them do not meet the declared characteristics and their speed degrades as they fill up. But this manufacturer also has SSDs from the top-end HyperX series, which are of higher quality and can be considered as an alternative to top-end expensive brands.

In general, budget and unpopular brands - like a lottery, may or may not be lucky. Therefore, I recommend that you refuse to purchase them if possible. And on the model of the recommended brands it is still better to look for reviews, since “there is a hole in the old woman”. Let me remind you that links to reviews of SSD drives are in the file, which can be downloaded in the "" section.

12. SSD Form Factor and Interface

The most popular today are 2.5 ″ form factor SSDs with a SATA3 (6 Gb / s) interface connector.

Such an SSD can be installed in a computer or laptop. Motherboard or the laptop must have a SATA3 (6Gb / s) or SATA2 (3Gb / s) connector. Correct operation when connected to the first version of SATA (1.5 Gb / s) is possible but not guaranteed.

When connected to the SATA2 connector, the read / write speed of the SSD will be capped at around 280MB / s. But you will still get a significant performance boost over the normal hard disk(HDD).

Plus, the access time, which is 100 times lower than that of the HDD, will not go anywhere, which will also significantly increase the responsiveness of the system and programs.

The more compact SSD form factor is mSATA, which is based on the SATA bus but has a different connector.

The use of such an SSD is justified in ultra-compact computers, laptops and mobile devices (tablets) with an mSATA connector, in which it is impossible or undesirable to install a conventional SSD.

Another more compact SSD form factor is M.2. This connector replaces mSATA, but is based on the faster PCI-E bus.

Motherboard, laptop or mobile device(tablet) must also have an appropriate connector.

Well and one more SSD type presented as a PCI-E expansion card.

Such SSDs have a very high speed (3-10 times higher than SSD with SATA3 interface), but they are much more expensive and therefore are used mainly in very demanding professional tasks.

13. Body material

An SSD enclosure is usually made of plastic or aluminum. It is believed that aluminum is better because it has a higher thermal conductivity. But since the SSD does not heat up significantly, this does not really matter and may not be taken into account when choosing a model.

14. Package contents

If you are purchasing an SSD for a computer and the case does not have mounts for 2.5 ″ drives, then pay attention to the presence of a mounting frame in the kit.

Most SSDs do not come with a mounting frame or even screws. But the included screw mount can be purchased separately.

The presence of a mount shouldn't be a weighty criterion when choosing an SSD, but sometimes a better SSD bundled with a mount can be purchased for the same money as a budget SSD with a separate mount.

15. Setting up filters in the online store

1. Go to the "SSD drives" section on the seller's website.
2. Select the recommended manufacturers (Crucial, Plextor, Samsung, SanDisk), you can also consider Corsair and A-DATA.
3. Select the size you want (120-128, 240-256 GB).
4. Sort the sample by price.
5. Browse SSDs starting with the cheaper ones.
6. Choose several models suitable for the price and speed (from 450/350 Mb / s).
7. Search the internet for their reviews and buy the best model.

Thus, you will get an SSD disk that is optimal in terms of volume and speed, meeting high quality criteria, at the lowest possible cost.

16. Links

SSD Samsung MZ-76E250BW
SSD A-Data Ultimate SU650 240GB
SSD A-Data Ultimate SU650 120GB