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SSDs have long migrated from the category of elite drives to the “must have” field. When assembling a more or less productive gaming, and just a working system, you already need to think about a high-speed drive, which is much faster and more stable than the good old hard drives.
That's just many stumble upon the first nuance: what type of memory is better? There are 3 categories:
- SLC (single) - 1 bit per cell;
- MLC (multi) - 2 bits per cell;
- TLC (triple) - 3 bits per cell.
The first category is used in the top segment, so we will not consider it. We are also interested in a more popular solution, namely MLC or TLC. Is there a difference between them, which is more productive, cheaper and more reliable, and which SSD is better?
Key differences
The first thing to note is the density of data recording. Each type of SSD has its own characteristics. For TLC chips, it is higher, since 3 bits are placed in a cell, when MLC has only 2. The larger the size of the SSD, the more often you will meet Triple options. And immediately the thought arises that you need to immediately run and buy the first option, without even considering all the others, but no.
In addition to density, there are also factors in the speed of reading and rewriting data. Have you ever wondered why TLC solutions with a similar amount of storage are cheaper? Because in MLC the number of cycles of complete erasure of information is 30-50% higher. If we talk about rewriting, then here the technology is 2-3 times ahead of its cheaper opponent. Another thing is that 1 GB of TLC memory will cost you much less.
Data security
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First, decide for what purposes the SSD will be used: for the system or as a data storage. Often it is purchased precisely for the installation of the OS and key programs, so that the latter react noticeably faster, because. Flash memory is static, which means that the read and write speed is several orders of magnitude higher than that of HDD due to the absence of mechanical parts.
Store something important while updating data frequently? Use MLC memory for its reliability. Are you going to create an archive of music, movies or games, as well as secondary programs? Then feel free to buy the option on TLC chips. Leave the Winchester under the "dump" of all the material available on the PC. Only the most frequently used applications and games should be placed on the SSD, so as not to take up high-speed disk space once again.
Life time
As for the duration of the “life” of the device, for TLC this figure is about 5-6 years, or about 1000 cycles of complete rewriting of information. For MLC, the figure rises to 7-8 years at 3000 cycles. But the "either-or" rule does not apply here. One of the chips may well fail, so do not rely on performance in 15 years.
But don't forget about the HDD either. Traditional magnetic disks have one important advantage over solid state disks - service life. Winchester, if it begins to "crumble", then gradually. This can be controlled in utilities like Victoria by checking the disk for bad sectors. SSDs "die" suddenly, but extremely rarely.
conclusions
What is the best memory? In terms of speed and cost of 1 GB, TLC leads, in terms of reliability - MLC. SSD is a very interesting type of memory, which should soon, if not completely, then thoroughly displace the HDD from its pedestal. Compare models before you buy. Watch tests, reviews, guides and draw conclusions. There are no bad drives. They are overrated.
The choice of SSD is now at a key place when building a gaming PC. If earlier they wanted to talk about a solid state drive, but were afraid to talk because of its cost, now some people are boldly transferring the entire system to this type of disk. Therefore, if you decide to improve your system, then you will have to find out which is better: TLC or MLC? Or is there some other option?
Advantages
Let's first try to figure out why everyone began to massively switch from HDD to SSD or use both drives together.
So, with respect to hard drives, SSDs are distinguished by complete noiselessness and high mechanical resistance. This is all due to the fact that they are devoid of moving elements. In addition, the solid state drive stands out for its stable file read times. And it does not matter where they are hidden in the system. The disk quickly loads them without braking.
The speed of reading and writing turned out to be higher. In some cases, it approaches the bandwidth of the well-known ones. Sometimes, faster slots such as PCI Express, NGFF, etc. are used for SSDs.
The next advantage is the number of input and output actions per second. This is realized thanks to the simultaneous launch of several processes and low latency. Now you do not have to wait until the disk makes a revolution to give access to data.
Not to mention the low power consumption and low sensitivity to external electromagnetic fields. And finally, the dimensions of the SSD. Due to the fact that we have a 2.5-inch drive or even M.2 format, you can even put it in a netbook.
Design
Before you figure out which type of SSD is better: TLC or MLC, you need to at least roughly understand what it is. To do this, consider the design of a solid state drive.
Most standard models are covered with a protective casing. If you look inside, you can see the controller. This is a conditionally small computer that has its own tasks. It controls the exchange of information between the device and the PC.
Buffer memory became one more element of SSD. DDR is implemented in a small volume, which does not depend on energy consumption. needed to store the cache. And the third element is flash memory. It is made by memory chips, which are already dependent on power consumption. It is this element that is responsible for recording your personal data.
Choice
Before we get into the details of which is better: TLC or MLC memory, some background information. In addition to the fact that initially choosing an SSD is not an easy thing, it turns out that we have to understand endless technical characteristics. Not everyone gets this kind of information easily.
But, unfortunately, in this case, you will have to figure out the types of memory. In addition to the main ones, which we will describe further, there are variations of V-NAND or 3D NAND. It is also better to know about them briefly.
Types
If you have ever seen a hard drive and a solid state drive, then you understand that they are structurally different and, accordingly, have a different mechanism of operation. The last option works with flash memory.
It is represented by special cells that are placed on the board in a special order. All of them are implemented on the basis of semiconductors. Hence the several types of SSD: TLC and MLC. What is better, everyone decides for himself or buys devices at random.
Memory storage
It so happens that flash memory on a solid state drive can be implemented through the principles of memory storage. Hence there are two groups. One has types based on the principle of reading and writing (NAND).
There is an option in which the memory is stored with different technologies: SLC and MLC. The first option is presented in such a way that there is only one bit of information for one cell. In the second case - 2 bits or more.
TLC memory is considered to be related to MLC. The only difference is that for the first option you can store 2 bits, and for the second - 3 bits. Now it remains to understand what this means, and which type of SSD is better: TLC and MLC.
Advantages
Since TLC is a subspecies of MLC, it is fair to say that the second type is predominant. What is its superiority? First, it has a higher speed. As practice shows, it can last a little longer. And also all its resources do not require large energy consumption.
But besides this, there are some disadvantages. The main one, of course, was the cost of a device with MLC.
different situation
There are also some problems that you may encounter. The fact is that the above cases are a common situation. In reality, developers can well confuse buyers. Therefore, thinking about which is better: TLC or MLC, you will be able to see:
- The same speed for both types when connected to SATA III. Some models may stand out with special speed based on TLC, due to the fact that they use the PCI-E NVMe interface. Although, as practice shows, the more expensive the drive, the faster it is. And with a high probability it will be based on the MLC.
- There are models in which a device with TLC has a longer warranty period than its older "brother".
- The issue of energy consumption may differ from the standard state of affairs. Understanding which is better: TLC or MLC, take a closer look at the interfaces with which they work. For example, TLC on SATA III is much more economical than MLC with PCI-E.
By the way, you can meet the difference in performance even when you install the drive first in one port and then in another. In this case, power consumption can vary greatly.
Other differences
The situations described above are not the only ones of their kind. Differences in speed parameters, service life and energy consumption may also depend on the generation of the device. It is easy to guess that if the model is new, then its old sample will be somewhat worse.
Solid state drive technologies are evolving, and we are getting increased volumes and amounts of free space, increased speeds and reduced temperatures.
As a result, it is impossible to say which SSD is better: TLC or MLC. You can definitely buy an outdated MLC model, which will noticeably differ in performance from the TLC for the worse. In this case, the cost of both devices will be the same.
Therefore, when choosing, pay attention to all the parameters, it is better to compare them immediately so that you do not regret the purchase later. Well, it is advisable to immediately set a budget for yourself. So it will be easier for you to group those models that suit you both in terms of cost and parameters.
Identification
If you decide to find out which is better: SSD TLC vs MLC, already when you purchased an SSD, you will want to identify the type of memory in your device. It has already happened that this information is not on the disks themselves. In addition, even if you install some utility for the test, you still won't get an answer. What to do in this case?
The easiest way is to go online. Here you can enter the name of the model and analyze it by reviews. There are even special sites that have the entire database of solid state drives. There is absolutely the entire specification for many popular models.
Problems
But not everything is so smooth. Perhaps some of the users came across an SSD from Silicon Power Slim. This is a fairly popular model that has been on the market for over 3 years. At the time of its appearance, it stood out for its low cost.
Although this story is complicated and long, it is worth knowing about it in brief. The cheapness of this disk was dictated by the choice of a new platform from a Taiwanese company. She was revolutionary. This was immediately clear from the characteristics of the devices. But there were several problems.
Firstly, the company did not take care to transfer all its models to this new platform, so some of the disks were sold on an outdated basis. Secondly, because of the desire to become popular, the developer had to make constant changes.
As a result, some models changed the type of memory and even the volume. A 120 GB SSD package could have contained a 60 GB drive. And the indication of the MLC chip did not mean at all that the user would receive a disk based on this type. As a result: a huge number of dissatisfied owners who got slow memory.
Manufacturers
Oddly enough, there are few developers who would produce and sell discs themselves. This is due to the fact that not all firms can have the necessary resources. Hence, a large number of companies that buy individual parts, and in their office just put everything together and sculpt a sticker.
Self-production is organized by the units. They care about the product because they care about the reviews their product gets.
The following major manufacturers work on memory:
- Intel.
- Micron.
- Samsung.
- Toshiba.
- SanDisk.
- Hynix.
The first two companies chose the same production technologies. This is because they use a joint venture.
Other options
If it has already become clear to you which is better: TLC or MLC, it remains to deal with one more type of memory. Sometimes in the reviews of solid state drives you can find incomprehensible designations: V-NAND, 3D-NAND, etc. This is another experiment that the manufacturer offers. Such a disk was made using other technologies.
In this case, the memory cells are placed not in one layer, but in several. Moreover, the memory is used by TLC and MLC. This fact is not indicated in all cases, but you must understand that the microcircuits themselves are of a familiar type.
In terms of performance, we can say that 3D-NAND is slightly better. Firstly, this is due to low cost and great opportunities. Secondly, multi-layer placement is more reliable and efficient. This can be proven by testing two models: "flat" and "volumetric" MLC.
conclusions
It is impossible to answer the question of what is better for the system: TLC or MLC. Very often, when users ask a similar question, you find yourself in an awkward position. Well, it's hard to understand what goals and objectives the buyer pursues. Perhaps he needs a super-productive system. Then he definitely needs a disc with MLC.
What if he needs a regular working PC. In this case, he may not need a solid state drive at all. All these are individual problems that everyone must solve on their own.
Times when SSD- disks were considered elite and inaccessible, before our eyes they become the property of history. Any user can afford to buy a solid state drive today, although it should be noted that, like traditional HDD, disks SSD differ from each other in speed, durability, capacity and other characteristics that determine their final price. When choosing a drive, you have to pay attention to all this, and therefore to the types of memory, among which MLS and TLS
.
Only here is what these abbreviations mean, which type of disk is better - MLS, TLS or SLC And how not to get lost in all these notations?
Let's figure it out.
Below we will look at how the main types of memory differ from each other, but for now, to make it easier for you to figure out what's what, let me say a few words about the solid state drive device. Disk SSD consists of three main components: controller, buffer and flash memory. The controller is a small device like a microprocessor with a program that controls the exchange of data between the disk and other computer components. Buffer memory or otherwise DDR is a small piece of volatile memory used for caching read/write operations. Finally, flash memory or NAND are the very cells in which the recorded information is stored.
This last one will be discussed today.
There are three types of non-volatile NAND-memory is already mentioned MLS , TLS and SLC . We do not set ourselves the task of revealing all the technical features of the device of memory chips, the main thing for us is to explain in the most accessible language how one type of memory is better than another. We only note that the key technological difference between MLS, TLS and SLC is the number of bits of information that one memory cell can store.
SLC
The oldest flash memory technology, which stands for Single Level Cell, that is, a single-level cell. One cell NAND-memory SLC has two thresholds and can only store one bit of information. Disks with this type of memory have a high read / write speed, while differing in enviable durability, on the other hand, they are small in capacity and, moreover, expensive. Due to the small volume and high cost of widespread use in desktop computers SLC- disks were not found, if they are used, then mainly on servers in data centers.
MLS
SSD-Disks with this type of memory are the most common. Abbreviation MLS stands for Multi Level Cell or multilevel cell. Unlike its predecessor, cell MLS-storage has not two, but four thresholds and can store two bits of data. Recording Density MLS-drives are higher, but it comes at a price. The use of different threshold voltage levels for encoding information, memory cells wear out faster. If the number of rewriting cycles SLC-disks is about 100,000, then the disks MLS it is 10000. The read / write speed in them is also lower, but the disks MLS much cheaper, due to which they are widely used.
TLS
Even higher recording density than MLS have discs with flash-memory TLS or Triple Level Cell (three-level cell) . A typical use case NAND-memory TLS are regular flash drives. Three bytes can be stored in one cell of the drive, but at the same time as the capacity increases, its performance and endurance decrease. So, the number of rewriting cycles of the average TLS-disc is 1000-3000. Does this mean that drives with this type of memory are unreliable? Not necessarily, and in general rumors about unreliability SSD TLS-drives are too exaggerated. Just look at the value of the parameter TBW, usually specified in the specifications of the drive, to make sure that its endurance reserve is guaranteed to last for several years.
Note: the TBW parameter specifies the guaranteed amount of data that can be written to disk. It is usually measured in terabytes and can be more than 100 TB.
So what type of memory to choose for your PC, MLS , TLS or SLC? An unambiguous answer to this question cannot be given, since everything will depend on the tasks assigned to the drive, as well as the ratio of price and quality.
If you intend to write to disk frequently, it is probably better to have MLS , but if you are going to use the drive as storage, then for these purposes it is quite suitable and TLS . Should I bother looking for SLC? Might be worth it if you have extra money and want a super fast system, but of course you have to look at the specs. Models SSD- there are a lot of disks, they all differ from each other in terms of characteristics, and upon careful comparison, it may very well turn out that the choice of a disk with memory TLS will be more justified and rational than buying a disk with more reliable and faster memory under ideal conditions MLS.
There are, and now let's look inside and see what parts it consists of, what affects the capacity of the disk, its speed performance, durability. After all, this, in the end, depends on the price, which is actively involved in deciding which SSD to buy, for what purposes to use it, will you have to make any compromises, find out which is better - MLC or TLC? Or splurge and find an SLC?
Components of an SSD
What is this "TLC" yes "MLC"? What is it all about? Now we will understand, because it is from this abbreviation that one should start when choosing a drive. Only, since we decided to look into the insides, we will briefly describe what the SSD disk consists of:
- Controller. A sort of microcomputer with its own program that controls the exchange of data between the drive and the computer. It also performs a lot of maintenance tasks for the SSD drive.
- Buffer memory (DDR). A small amount of non-volatile memory used for caching write/read operations.
- Flash memory (NAND). Non-volatile memory chips that store information written to disk.
All of these parts are important and play their part in achieving storage reliability and maximizing drive performance. We'll talk about the first two sometime next time, but today we'll focus on the types of NAND memory used in modern SSD drives.
Types of memory used
We will not go into technical details of how information is stored in memory chips and why it does not disappear when the disk is disconnected. Let's just say that all information is stored in memory cells, which are floating gate transistors. It is the level of charge stored on this gate that determines the value of a bit (or several) of information.
Moreover, one transistor is used to store not only one bit, but also two or three. This is due to the desire to increase the capacity of NAND-memory and reduce its cost in terms of a unit of stored data. During the development of the SSD, several types of memory have been developed.
SLC
The first solid-state drives that appeared used exactly this type of memory, which stands for Single-Level Cell (single-level cell). Each cell held only one bit of data. There is a voltage threshold that determines what is stored in the cell. If the read voltage is higher than the threshold, then a logical "1" is stored there, if it is lower, then a logical "0".
This technology is good for everyone: both the write / read speed is high, and the memory cells are durable, allowing repeated rewriting. The number of programming (writing) or erasing operations is called P/E-cycles (program/erase cycles). For SLC memory, the number of these cycles is about 100,000, which gives SSD drives with such NAND memory chips an enviable survivability.
Unfortunately, disks of this class are expensive, and they cannot boast of large capacities. Therefore, they have found their application mainly as drives in servers, data centers, etc.
MLC
It was possible to increase the capacity of memory chips by developing the Multi-Level Cell technology (multi-level cell). In this case, the goal was to store not one, but two bits of information in one cell. For this, 4 threshold voltages had to be introduced, each value of which corresponded to a certain combination of bits.
It was possible to reduce the cost of drives, while increasing the recording density. There were pluses, but there were also minuses. Several threshold voltage levels used to encode information have become sensitive to the quality of microcircuits, to the degradation of their properties. The number of P/E cycles has been reduced to about 10,000. There is a variant of E-MLC used for drives oriented for server use. They have a P/E of approximately 30,000.
At the same time, the time of reading from the cell, writing to it, and erasing increased. But this made it possible to reduce the cost and, accordingly, reduce the final cost of such disks, contributing to their wide distribution.
TLC
The development of new methods for compacting information stored in a memory cell, and at the same time the desire to further reduce the cost of SSD drives, led to the emergence of Triple-Level Cell technology (three-level cell), which allows storing 3 bits in one cell. Density has increased, but so have the time spent on writing, erasing, and reading. At the same time, the P / E parameter decreased even more, and began to amount to 1000-3000.
This is due to the fact that already 8 threshold voltage levels had to be entered, the values of which indicate which combination of bits is stored in the cell. The reliability of data storage has become more dependent on the quality of microcircuits, the rate of deterioration of their properties, the change in the voltage level in the gate due to physical processes in the crystal lattice, moreover, in order to correctly read information from the cells, it was necessary to determine the voltage level in the transistor with very high accuracy.
All this had a negative impact on the durability, speed of data exchange, but it made it possible to significantly reduce the cost of the final product. Such memory began to be used in budget models of SSD drives.
However, rumors about the unreliability of SSDs with such memory are greatly exaggerated. Among the characteristics of SSD drive models, you can find such a parameter as TBW (Total Bytes Written, i.e., the guaranteed amount of data that can be written to a disk), usually measured in TB (terabytes). For example, at the time of writing, my 128 GB Plextor S2C PX-128s2c drive has a TBW value of 75 TB. At the moment, more than 235 TB have already been written to the disk without any errors, and there are no signs of problems.
No matter how they criticize, no matter how dismissively they treat TLC memory, but it is actively developing, many manufacturers produce models on this type of NAND memory. Apparently, this technology is the future, at least for devices for the mass market.
True, not quite in its original version. The 3D TLC NAND technology that is replacing it, based on the use of three-bit cells, offers a very interesting option with the correction of many shortcomings, but all this is worth devoting a separate material to 3D-NAND.
Conclusion. What to prefer, MLC or TLC
The main arguments against TLC-based SSDs are slow read/write performance and short life span. Let's clarify how true this is.
If we compare the speed with that of analogues on the MLC, and even more so on the SLC, then yes, it is lower. No wonder TLC drives are a budget class, however, the best representatives are close to models based on MLC chips. On the other hand, even inexpensive SSD options are several times faster than conventional hard drives, and even after you start using solid state drives, you will not want to go back to a regular hard drive. This applies, first of all, to the system disk, using it to load "heavy" programs or games.
As for reliability… Yes, 75 TB, or 150 TB, might seem like a bit. Is that so? I am writing this text on a laptop in which for more than six months a Plextor PX-256M6MV of the mSATA form factor has been working as a system disk. For all the time I recorded a little more than 1.6 TB on it, despite the fact that the computer is used every day. How soon will I run out of the guaranteed 150 TB, and why does it have to fail?
Of course, using such drives in a data center or a working server may not be a good idea, but for home or office use, especially if you don’t chase speed records, this is more than a worthy option, despite the fact that the cost of the drive is quite acceptable. Another thing is the durability of information storage. Using a disc to write something important to it and put it on a shelf can be a source of disappointment if after six months or a year or two it turns out that the data is damaged or missing. The disk suddenly became empty, although something was written on it. In this regard, traditional hard drives are more reliable.
A bunch of SSD as a system drive and a traditional “hard” for all sorts of things is the optimal bundle today, a combination of download speed for everything you need and capacity for everything else that is necessary, but not demanding on download speed.
