Review of Samsung's stylish Galaxy Alpha (SM-G850F). Samsung's Stylish Galaxy Alpha (SM-G850F) Review ⇡ Random Reads and Writes, IOMeter

The Samsung SSD 840 PRO family has been on the market for two years now, and our tests have consistently ranked the top drives - although quite a few other high-end SSDs have appeared during that period. Even today, the 840 PRO is able to compete for the leading position, but Samsung has prepared a new leader - the SSD 850 PRO. But in this case, the development is not only evolutionary, as Samsung first used 3D V-NAND memory in a consumer-grade SSD. Unlike MLC NAND memory, the new type of memory promises to be more reliable and faster, and also provides a higher level of storage density.

Samsung's biggest innovation is in the flash memory it uses. More recently, we highlighted the technology leadership of Crucial, which uses 16nm MLC NAND at 256Gbps per die, but Samsung has gotten more radical changes. Last year, the first family (3 bits per cell) appeared to receive our award. The new Samsung SSD 850 PRO range has undergone a fundamental change in flash memory technology.

All types of SLC, MLC or TLC flash memory have one thing in common: the cells are two-dimensional, that is, they are located on the plane of the crystal. And to increase the memory capacity, it is necessary to increase the die area. Of course, today manufacturers install "sandwiches" of several memory crystals, which allows chips to be increased in height, and not just in area. But here, too, not everything is going smoothly, since the quality of the signals for crystals in such a stack decreases. In Samsung's case, 3D V-NAND memory cells are already three-dimensional, they are concentric cylinders and can be stacked much easier.

The technical specifications are shown in the following table:

We'll first look at the technology of the new 3D V-NAND flash memory, and then move on to benchmarking Samsung's new 850 Pro family.

• Custom PCs Application
• SATA 6Gb / s interface, compatible with SATA 3Gb / s and SATA 1.5Gb / s interface Interfaces
• 100 X 69.85 X 6.8 (mm) Dimensions (WxHxD)
• max 66.0g Weight (g)
• Up to 550 MB / s * Data transfer rates are based on Samsung internal testing. The data transfer rate depends on the equipment used and the testing conditions. Sequential reading
• Up to 520 MB / s * Data transfer rates are based on Samsung internal testing. The data transfer rate depends on the equipment used and the testing conditions. Sequential write

• General features
  • Application Custom PCs
  • Capacity 2048 billion bytes * A certain part of the memory can be occupied by system files, so the amount of memory available to the user may be less than specified in the technical specifications.
  • Form factor 2.5 inch
  • Interface SATA 6Gb / s interface, compatible with SATA 3Gb / s and SATA 1.5Gb / s interface
  • Dimensions (WxHxD) 100 X 69.85 X 6.8 (mm)
  • Weight (g) max 66.0g
  • Main memory 32-layer Samsung 3D V-NAND architecture
  • Controller Samsung MHX controller
  • Buffer memory Samsung 2GB Low Power DDR3 SDRAM
• Peculiarities
  • TRIM support Yes
  • S.M.A.R.T support Yes
  • GC (garbage collection) Yes
  • Encryption support AES 256
  • WWN support Yes
  • Sleep support Yes
• Specifications
  • Sequential reading Up to 550 MB / s * Data transfer rates are based on Samsung internal testing. The data transfer rate depends on the equipment used and the testing conditions.
  • Sequential write Up to 520 MB / s * Data transfer rates are based on Samsung internal testing. The data transfer rate depends on the equipment used and the testing conditions.
  • Random Read (4KB, QD32) Up to 100,000 IOPS * Data rates are based on Samsung internal testing. The data transfer rate depends on the equipment used and the testing conditions.
  • Random Write (4KB, QD32) Up to 90,000 IOPS * Data rates are based on Samsung internal testing. The data transfer rate depends on the equipment used and the testing conditions.
  • Random Read (4KB, QD1) Up to 10,000 IOPS * Data rates are based on Samsung internal testing. The data transfer rate depends on the equipment used and the testing conditions.
  • Random Write (4KB, QD1) Up to 36,000 IOPS * Data rates are based on Samsung internal testing. The data transfer rate depends on the equipment used and the testing conditions.
• Operating conditions
  • Average power consumption (system level) * Wed: 3.5W * Max: 5.8W (Peak)
    
  • Standby Power Consumption Max. 60mW
    * Power consumption may vary based on system configuration
  • Supply voltage 5V ± 5%
  • Reliability (MTBF) 1.5 million hours mean time between failures (MTBF)
  • Operating temperature range 0 - 70 ℃
  • Shock resistance 1,500G & 0.5ms (half sine wave)
• Accessories
  • Installation kit No
• Software
  • Additional software Magician SSD Management Software
• Guarantee 10 year warranty / write resource: 450 trillion bytes

The Samsung 850 Evo series drives are rated by industry experts as combining low price with extremely impressive performance. In terms of operating speed, the corresponding devices are comparable to many premium disk models. What are the main technological advantages of these solutions? How do users rate their effectiveness?

General device information

The Samsung 850 Evo is a series of SSDs. These devices are characterized by a large capacity and a high level of reliability. They are in demand when solving problems related to the provision of high-speed data transmission.

Samsung 850 Evo devices are manufactured using the 3D V-VAND architecture, which is characterized by the use of cylindrical cells, adapted to eliminate interference arising from the interaction of device components. The provision of a large capacity of devices is carried out by placing the elements in several layers. At the same time, the reliability of file storage, as well as the speed of their transfer, does not decrease.

Among other notable features of the devices in this series is the ability to switch to RAPID mode, in which the drive starts operating at an even higher speed. This is achieved, in particular, due to the fact that the device begins to use the available volume random access memory PC as cache.

The Samsung 850 Evo features effective energy-saving technologies. According to experts, in a number of modes the device is capable of consuming tens of times less electricity in comparison with outdated storage models.

The series of disks under consideration contains a number of high-tech solutions in the field of file security. These include AES encryption, dynamic thermal protection.

It can be noted that the introduction of the Samsung 850 Evo series devices on the market was preceded by the successful work of the Korean corporation to create and ensure successful sales of the SSD 830 series devices, as well as the 840 Pro series, which were attributed by experts to best devices type SSD in the upper price segment. The company did not forget about products for the mass segment: for example, the 840 and 840 EVO devices were introduced to the market.

Subsequently, Samsung Corporation continued to develop in the field of multilayer crystals, and one of the results of their practical implementation was the release of 32-layer 850 Evo drives. This device was launched in the mass segment. In the premium segment, Samsung has introduced the 850 Pro, which is characterized by an exceptionally high combination of performance and reliability.

A storage device as a product of technological modernization

What are the features of the 850 Evo series?

Above, we noted that these devices are based on the best Samsung developments in previous products. So, the main components that were installed in the 840 series products - TLC memory, a branded controller, as well as the TurboWrite solution, were duplicated in new series devices. In addition, a number of updates were also implemented in it - in particular, instead of the proprietary MEX controller, the manufacturer installed an improved MGX hardware component.

The TurboWrite technology has also been added to the Samsung 850 Evo series.

3D V-VAND technology

Probably the most notable component of the new series of drives is 3D memory, which is an amalgamation of 3D NAND and TLC NAND solutions. The new technology made it possible to eliminate the disadvantages that characterize the use of the two previous ones separately.

The use of the 3D V-NAND concept allowed Samsung to implement a 40 nm process technology in the new product while retaining the ability to use crystals with an area smaller than, in particular, using conventional MLC NAND technology, which is produced according to the 16 nm process technology. In turn, cells of 40 nm are characterized by greater wear resistance, as well as stability in operation.

Another benefit of the corresponding updated technology that powers the Samsung 850 Evo SSD is that it delivers faster performance by reducing read and write times. Thanks to recording into one separate memory cell not 2, but 3 bits of data, the capacity of the crystals used in devices of the series under consideration can reach 128 Gbps. Moreover, these crystals have an area that is about 2 times smaller than that of the corresponding TLC NAND components in a conventional modification with the same capacity, which are produced according to the 19 nm process technology.

It can be noted that the manufacturer gives a 5-year warranty for the devices. This is one of the most competitive indicators on the market.

It will be useful to consider what the corresponding devices look like.

The appearance of the drives

Regardless of the capacity of the Samsung 850 Evo - 250GB or 1TB, all devices in the line look almost the same. Outside, they have a compact - 7 mm thick, black aluminum body. On the reverse side of it there is a label, from the contents of which you can find out the exact name of the drive model, as well as its serial number.

If you open the cover of the enclosure, you will find that, depending on the specific size of the disc, the contents may differ. For example, the 250 GB model has a smaller PCB than the 500 GB model. But in both cases, the size of the corresponding hardware component is small, that is, we can say that the body of the device could be even thinner, it has empty spaces.

Installing the Drive on a PC

How is the Samsung 850 Evo installed in a PC? Installing the device is very simple. Most modern PC cases have slots for installing drives the size of the 850 Evo - 2.5 inches. It is necessary to position the drive appropriately, and then connect 2 cables to it - power supply and data transfer.

After that, you need to switch the PC controller to AHCI mode. This, however, may require an update. BIOS version- using the firmware from the official website of the PC motherboard manufacturer. The drive is recognized in the system without problems. If necessary, you can use branded programs to configure the system and monitor disk performance.

Storage resources

Using a Samsung 850 Evo 1TB SSD, you can write about 82GB of files per day to it. A similar resource has a disk with a capacity of 500 GB. Slightly smaller, but nevertheless impressive resource, have younger modifications of devices - 120, 250 GB. They can record about 42 GB of information per day.

Thus, the SSD series in question is designed for a long lifespan. Even the smallest models in the Samsung 850 Evo range - 120GB or 250GB - have a capacity comparable to that of many premium models.

Work speed

The speed of the devices in this series is also impressive for experts. At the same time, the indicators characterizing the younger model of the 850 Evo line, as shown by tests carried out by experts, are not too inferior to those of the premium model, the 850 Pro.

In many respects, good speed indicators are achieved due to the use of TurboWrite technology, as well as the use of a fast cache. Which in the Samsung 850 Evo 250GB model is 3 GB, in the 500 GB modification it is 6 GB, and in the 1 TB disk the cache size is 12 GB.

The capabilities of the drives under consideration in terms of ensuring the speed of data recording again allow us to speak about their competitiveness in relation to premium products.

Testing drives: read and write speed

Let us now study the practical results of experts studying the capabilities of the drives of the series in question. As for the reading mode, high technologies implemented in the corresponding devices allow achieving the highest rates here.

But regarding the recording, the test results may be different depending on the specific modification of the device. So, for example, a 500 GB drive has performance comparable to those of the older model. In this sense, when choosing - Samsung 850 Pro or 850 Evo - the user gets a clear advantage in price if he prefers the second model, despite the fact that in terms of speed it is practically not inferior to the older modification.

In turn, the model in the 250 GB version is significantly inferior to the more capacious version in terms of sequential write speed. This is largely due to the relatively small size of the cache, which has the corresponding modification of the drive - its size is 3 GB. Which, at the same time, is sufficient to solve a large number of user tasks in practice.

Drive Testing: Random Read Speed

Another interesting performance metric for the Samsung 850 Evo is the random read speed test. Equipped with an updated MGX controller, the devices have significantly improved performance over previous modifications, experts say.

At the same time, especially high results were shown by the 500 GB model of the drive. Its performance allows it to be described as actually a leading product in the segment in the context of considering performance in the appropriate mode.

Drive Testing: Random Write Speed

What is the device's performance in random read speed mode?

As the tests carried out by experts show, everything is also in order here. However, as the queue depth increases, the performance of the 850 Evo line decreases. But even though this feature, the devices can be characterized as extremely competitive in the respective mode of use.

Testing Drives: Copying Files

One of the most indicative criteria for evaluating a drive's performance is the file copying speed achieved when using a particular device. Here, the performance of the devices in this modification is, again, very decent. Especially when it comes to modifying a 500 GB drive.

In turn, the performance of the 250 GB modification is somewhat more modest. Nevertheless, this contributes to a high assessment of the competitiveness of the device when used in the appropriate mode, which generally reflects the typical user load on the drive.

In some modes of working with files, the difference between device modifications of 200 and 500 GB is completely insignificant. Therefore, in practice, the user may not notice it at all.

In general, performance tests of devices in the 850 Evo line from Samsung allows us to say that the Korean brand has ensured a presence on the market of a largely unique product: having, on the one hand, a relatively low price, on the other, technological advantages that make it comparable in functions and productivity with premium solutions.

This approach, according to experts, Samsung was able to implement due to purposeful and competent work on the consistent improvement of the developments of the past years, as well as complementing them with relevant innovations that make the devices even more competitive.

The South Korean manufacturer began "experiments" with three-bit TLC memory on customers back in 2013. The last generation - 840 EVO - I think was successful, although there was a lot of controversy about the reliability of these SSDs, because the number of cell rewriting cycles for TLCs is less than that of MLC / SLC. In terms of speed characteristics, this type of memory is also inferior, since eight voltage levels are used to store three bits of information, the removal of which takes more time. MLC has half the size. This increases cell wear. With the introduction of new technological standards, the problem is only aggravated, since a decrease in the cell size (thinning of the dielectric layer) leads to a charge leakage from the floating gate.

The 3D V-NAND structure solves both problems. First, TLC layered packaging takes up less space than, for example, planar MLC. Bottom line: there is no point in chasing a decrease in the technical process. The memory in the 850 PRO and 850 EVO lines is manufactured according to 40nm "prehistoric" standards, which significantly increases its reliability. Samsung claims that the probability of errors when reading data from TLC V-NAND is 10 times lower than that of "regular" planar TLC. Words go with deeds: All 850 EVO drives are backed by a 5-year warranty. Competitors offer mostly 3 years.

Secondly, the TLC V-NAND reduces the number of pulses applied to the gate control cells. Increased productivity. As a result, the 850 EVO line is slightly inferior to the 850 PRO in terms of performance. At the same time, drives of different sizes have approximately the same performance. There is no serious bias (according to the characteristics) between the models.

The review included two SSDs with the same volume of 500 GB at once. SATA 3.0 and M.2 drives have similar technical characteristics... Of course, 40nm TLC V-NAND with 128Gb die capacity is used everywhere. There are four models in the 850 EVO SATA 3.0 series. The 1TB device stands out somewhat from the crowd as it is based on the more powerful MEX controller. The same processor is used in the 850 PRO solid-state devices. There are only three M.2 drives. In all cases, a 2280 format printed circuit board with two keys "B" and "M" is used.

Over the past years, Samsung has been able to become one of the key players in the solid state drive market. The company's strategy lies in the complete vertical integration of production from start to finish, which allows it to keep the lead in the implementation of new promising technologies. By simultaneously developing and releasing both controllers and flash memory, the company gains a huge engineering advantage since commissioning and debugging new designs does not require any outside involvement. And we have already seen examples of the implementation of this advantage: here it is appropriate to recall the SSD of the 840 series, which became the first mass products based on three-bit TLC NAND. It is thanks to this Samsung technology was able to conquer the market of mass flash drives. Using inexpensive Samsung-made TLC memory, the 840 series, and later the 840 EVO, offered an excellent combination of performance and price, which ultimately made them one of the most popular solutions.

Now, two years after the introduction of TLC NAND, Samsung is once again making a major breakthrough in technology with the groundbreaking 850 Pro Series, the first consumer SSDs to use the all-new 3D MLC NAND. Despite the fact that Samsung 850 Pro is not officially supplied to the Russian market yet, our laboratory managed to get and test a copy of a promising solid state drive... Whether this SSD will become a worthy successor to the traditions of the 840 Pro model and whether it will take the place of the best flash drive for personal computers, we will find out in this material.

⇡ Samsung V-NAND: the new flash paradigm in action

NAND memory has changed the entire storage market. Drives based not on traditional hard disk drives but on flash memory have been able to establish fundamentally higher levels of performance, and this has made them one of the most interesting computer technologies of the last decade. At the same time, NAND memory is far from a new invention. In fact, it appeared back in the 70s of the last century, but for a long time it simply could not penetrate consumer devices due to its high cost. However, technological progress in the end was able to make such memory affordable, and now it has become simply impossible to imagine a modern productive computer without an SSD stuffed with MLC or TLC NAND.

Improvements in semiconductor devices have played a major role in reducing the cost of flash memory. technological processes which are used to produce NAND crystals. Reducing production rates reduces the area of ​​the resulting crystals, increasing the storage density in them of information, which ultimately leads to a decrease in the cost of solid-state drives. For example, the massive penetration of SSDs into the consumer market began with the transfer of flash memory crystal production from 50nm to 30nm processes. Nowadays, technical processes with rates less than 20 nm are in use, and the cost of flash drives quite naturally continues to fall.

However, it should be borne in mind that the improvement of technical processes to infinity is impossible. Moreover, manufacturers of flash memory are already feeling the imminent and imminent approach of technological limits. The fact is that with the thinning of production standards and a decrease in the geometric dimensions of transistors, the reliability characteristics of flash memory decrease. For example, memory manufactured using 50nm technology was able to withstand up to 10,000 rewriting cycles, while today's 20nm NAND is designed for 3,000 programming-erase cycles at best. In other words, there are serious obstacles to further scalability of traditional NAND memory, which, like other semiconductor devices, is still subject to Moore's Law.

Fortunately, all of this does not mean that progress will slow down. Fundamentally new ideas come to the rescue, making changes in the design principles of flash memory and allowing to increase the density of information storage without reducing the size of the cells.

The first such idea was an attempt to increase the bit width of cells when moving from SLC NAND to MLC and TLC memory, where each cell stores not one, but two or three bits of information. This is achieved by introducing a larger number of signal voltages. While SLC cells use only two voltage levels, corresponding to logic states 0 and 1, the MLC already uses four voltages, and the TLC uses eight. However, in reality, this path is a dead end. If the transition to MLC can be considered already a success, then there are very serious problems with TLC NAND, which, as practice shows, inhibits its spread. The point is that the use of a large number of voltages in the floating gate of the cell is possible only if this gate is massive enough to hold a significant number of electrons. But the introduction of technical processes with fine norms, on the contrary, reduces the size of the cells, so the release of TLC-memory using technologies of the 10-nm class becomes economically unprofitable. Not only the yield of suitable crystals decreases, but also the reliability of signal recognition, which requires the introduction of more complex analog-to-digital conversion circuits and data integrity control into the control logic. Plus, another serious problem arises sharply - the mutual influence of cells, the electric field of which generates interference processes.

Obviously, some other approach is required. And an approach that should be a catalyst further development flash memory market over the next few years, is three-dimensional (3D) NAND. Its essence lies in the fact that instead of increasing the data storage density on the two-dimensional plane of a semiconductor crystal, it is proposed to switch to the use of vertical measurement and arrange cells not only planar, but also in layers.

The first to mass production of such a memory was able to enter Samsung, in whose performance this memory is called V-NAND (from the word Vertical), while other manufacturers such as Micron, Toshiba, SanDisk and SK Hynix are going to join promising technology during 2015.

The most interesting thing is that 3D NAND makes the race of nanometers completely unnecessary. For example, the same Samsung company, after introducing 19-nm technology for the manufacture of its planar memory, did not take the next step, but, on the contrary, with the transition to the release of V-NAND, rolled back to the 40-nm technical process. The high density of information storage, which is not inferior to the density of conventional NAND, which is produced by other manufacturers using 16-nm and 19-nm technical processes, was provided by a multilayer layout. But the main gain was found on the other hand: mature technologies and fairly large semiconductor elements significantly increased the memory resource and made it possible to avoid problems with a low yield of suitable crystals.

Samsung was able to introduce trial first-generation V-NAND SSDs last year. These pioneering, server-oriented SSDs have proven their worth. The memory used in them, which combines 24 vertical levels with cells, provided a 20 percent increase in performance, approximately doubled the reliability and significantly improved the economy of flash drives. This gave Samsung every reason to continue developing in the same direction. And now the company is ready to introduce the new technology to the mass market: the second generation V-NAND with 32 vertical levels and a new consumer storage based on it - the SSD 850 Pro, have appeared in Samsung's arsenal.

It should be noted that V-NAND not only assumes the arrangement of cells in layers, but also introduces some changes to the basic structure of flash memory cells. Along with the structural transformation, Samsung has taken advantage of the Charge Trap Flash (CTF) technology, a "charge trap flash" developed by the company's engineers back in 2006. The idea is that the charge is not stored in a doped polysilicon floating gate, but in a thin non-conductive silicon nitride layer. This technology is easily adaptable for three-dimensional design: the dielectric is placed between the control gate and the semiconductor channel in concentric cylinders, which ultimately increases the reliability of the entire circuit and reduces the likelihood of structural defects in multilayer production. In addition, CTF technology can reduce the voltage level required to program cells. And this, naturally, has a positive effect on their lifetime.

As a result, the Samsung V-NAND resource has grown significantly: the same 32-level flash memory crystals found in the Samsung 850 Pro can withstand up to 35,000 programming-erase cycles. That is, they are orders of magnitude more robust than modern flat MLC NAND, which is usually used in consumer SSDs. In addition, lowering the programming voltages has a positive effect on both power consumption and write performance.

Another important advantage of V-NAND is its compactness. The second-generation V-NAND semiconductor crystals used in the Samsung 850 Pro, produced using 40nm technology, have a capacity of 86 Gbps, while their area is about 95 mm 2. Thus, the storage density in V-NAND exceeds the storage density in 16nm planar flash memory chips manufactured by Micron by about 20 percent. In addition, Samsung, carrying out a full production cycle from start to finish, has the ability to pack up to 16 V-NAND cores in a single chip. And this means that the maximum volume of one three-dimensional flash memory chip can reach 172 GB.

Of course, many of the advantages of V-NAND technology will only appear later. For example, the SATA 6 Gb / s interface used today, coupled with the AHCI protocol, does not allow the full speed of the new memory to be revealed, and in future SSD models with the interface PCI Express she will be able to sparkle with new colors. Most importantly, 3D memory technology is highly scalable. The capacity of simple flat NAND chips is unlikely to exceed 128 Gbps, and V-NAND allows you to seamlessly add new layers and thus increase capacity. So, Samsung plans to release terabit crystals in 2017, and there is no reason why this milestone may not be taken. Along the way, V-NAND, produced according to fairly mature technical processes, can easily be transferred to a TLC design, and this will not lead to a catastrophic decrease in reliability. However on this moment such possibilities are not even considered, and in the coming years the emphasis will be on scaling memory in the vertical dimension.

In the near future, we can expect the widespread adoption of V-NAND in many Samsung products. For the sake of this memory, the company has launched a special plant in the Chinese city of Xi'an, which by the end of this year should reach full power... It is curious that the 40-nm process technology used at this plant made it possible to get by with fairly cheap production equipment, and the addition of new layers to the three-dimensional NAND practically does not require any additional investment. For example, 32-layer memory is manufactured on the same production lines that previously produced 24-layer memory. And this means that another plus new technology there is the possibility of saving on technical re-equipment of production while increasing the density of data storage.

It turns out that V-NAND can boast all possible advantages, and at once. It has lower latencies, is very reliable, offers high storage density, is energy efficient, and its production cost is relatively low. And if such memory is placed in a drive with a modern controller, then it seems that an amazing model should turn out that will surpass everything that has been released so far. Has Samsung released such a model? Let's take a closer look at the 850 Pro.

⇡ Samsung 850 Pro Specifications

The new flagship Samsung 850 Pro drive is a logical continuation of the company's line of consumer SSDs. In doing so, Samsung is innovating strictly consistently, and V-NAND is the 850 Pro's only fundamental advantage over its predecessors. This drive continues to use the familiar SATA 6Gb / s interface and builds on the familiar eight-channel MEX controller found in the 840 EVO series for a long time. Moreover, the MEX controller, which is based on three cores with ARM architecture, in the new model even retained its operating frequency of 400 MHz. However, for the sake of fairness, we note that in the past flagship Samsung flash drive, the 840 Pro, the MDX controller similar in architecture worked at 300 MHz.

At the same time, micro Samsung program The 850 Pro is almost completely rewritten. Support for V-NAND is implemented precisely through it, and the lower latencies for writing and erasing information offered by this memory, a higher resource of cells and all other characteristic features require special optimizations.

As a result, the Samsung 850 Pro series received the following set of features:

While much of the performance of the Samsung 850 Pro is constrained by its capabilities SATA interface 6 Gbps, even simple formal specifications allow you to feel the power hidden in this flash drive. Pay attention to the speed characteristics of the younger model with a capacity of 128 GB. This modification practically does not lag behind its older brothers, despite the fact that the controller in it cannot use the alternation of devices in its channels. Typical write speeds for 128 GB SSDs with SATA 6 Gb / s are in the order of 300 MB / s, but the Samsung 850 Pro of the same size produces an almost possible maximum of 470 MB / s. This clearly indicates the significantly higher write speeds provided by V-NAND technology. It looks very likely that when Samsung finally releases a V-NAND-based PCI Express flash drive, it will be a bombshell. However, we still have to live up to this wonderful moment.

The second advantage of V-NAND, clearly seen in the table Samsung specifications 850 Pro - high reliability. All modifications, including the youngest model with a capacity of 128 GB, have a declared write resource at the level of 150 TB, that is, 80 GB per day for a five-year period. And that's not just more than promised for any other consumer SSD model. The manufacturer emphasizes that such a resource was established not for technological, but for political reasons, so that the Samsung 850 Pro does not create internal competition for server models with a higher guaranteed reliability... In fact, the amount of data that can be written to new SSDs with 3D flash memory is measured in petabytes. In other words, the problem of exhaustion of the recording resource during typical desktop use for the Samsung 850 Pro should not be at all. That is why the warranty period has been extended to 10 years.

I would like to note the implementation in the Samsung 850 Pro of a number of technologies that are useful when installing this drive in mobile computers. In particular, this SSD has improved support for the DevSleep state, which allows you to send the drive to sleep mode with a consumption of about 2 mW. The controller also supports temperature monitoring, and when the drive heats up to critical conditions, throttling is automatically turned on.

Implemented in Samsung 850 Pro and hardware encryption using the AES algorithm with a 256-bit key. As with the company's earlier SSDs, the crypto engine is compliant with the Windows eDrive (IEEE 1667) and TCG Opal 2.0 specifications, which means that encryption can be managed from within the operating system, for example through standard BitLocker.

To what has been said, it remains only to add that Samsung belongs to the small number of manufacturers who care about providing users with convenient service utilities. With the Samsung 850 Pro, the Samsung Magician program works great, with a comprehensive set of features, including firmware updates, flash drive health monitoring, operating system optimization, and more.

Separately, it is worth mentioning the RAPID software technology implemented in Samsung Magician, which can be paired with the new product and allows you to allocate a part of the RAM for caching calls to the SSD. At the same time, the data exchange rates, of course, increase, but the price for this is the risk of losing information cached in memory in the event of sudden power outages, reboots or system freezes. At the same time with Samsung release In the 850 Pro, the manufacturer updated the RAPID technology to version 2.0, and now it can allocate either 1 GB of memory or 4 GB for the cache, depending on whether more or less 16 GB of RAM is installed in the system.

⇡ Exterior and internal structure

We tested the Samsung 850 Pro with a capacity of 256 GB. In terms of performance, this model, like its 512 GB and 1 TB counterparts, has the highest possible performance.

Externally, the Samsung 850 Pro differs little from previous Samsung flash drives. This SSD uses the exact same 7mm high 2.5-inch chassis as the last flagship model, the 840 Pro. The external color is black, the front surface is painted with the Samsung logo and an orange square, in one form or another present on all SSDs of the company of the same form factor. There is a label on the back of the case, from which you can get information about the name and capacity of the model, its article and serial number.

The insides of the Samsung 850 Pro 256 GB are much more interesting. The first thing that catches the eye is that this SSD is based on a stripped-down PCB. This board contains only six microcircuits.

The first microcircuit is the Samsung MEX controller itself. It should be noted that there are no heat-conducting pads on it, and it does not come into contact with the body. That is, the manufacturer is sure that the heat dissipation of the controller is negligible. A memory chip is installed above the controller. In our case, this is a 512 MB LPDDR2-1067 used as a buffer.

As for the remaining four chips with flash memory, their set turned out to be a little unusual. Since the storage capacity of the V-NAND crystals used in the Samsung 850 Pro is 86 Gbps, two different types microcircuits: two microcircuits with four cores and two microcircuits with eight cores. Thus, the controller addresses 24 cores on eight channels, that is, it uses three-fold interleaving of devices in each channel. However, as we saw from the performance characteristics, this is not a problem and the Samsung 850 Pro 256 GB shows the maximum possible speed under any load conditions.

If you add the 24 86 Gb poisons together, the total flash storage capacity in the Samsung 850 Pro 256 GB is actually 258 GiB. Of these, only the traditional 238.4 GiB is available to the user, and the remaining 7.6 percent of the capacity is allocated to the operation of garbage collection technologies, wear leveling and, probably, to a replacement fund, the need for which for memory with a resource of 35 thousand rewriting cycles raises some doubts.

However, the Samsung 850 Pro printed circuit board does not have any capacitor banks, which means that this SSD does not provide any special means of preserving the integrity of information in the event of a sudden power outage. This is another reason why a consumer drive built on V-NAND with an almost infinite resource cannot be classified as a server solution.

⇡ Testing methodology

Testing is done in the operating room Microsoft system Windows 8.1 Professional x64 with Update, which correctly recognizes and manages modern solid state drives. This means that the TRIM command is supported and actively used during the tests, as in normal day-to-day use of the SSD. Performance is measured with drives in a "used" state by pre-filling them with data. Drives are cleaned and serviced by the TRIM command before each test. There is a 15-minute pause between individual tests, which is allotted for the correct practice of garbage collection technology. All tests, unless otherwise noted, use randomized incompressible data.

Applications and tests used:

• Iometer 1.1.0

1. Measuring the speed of sequential read and write data in blocks of 256 KB (the most typical block size for sequential operations in desktop tasks). The estimation of the speeds is carried out within a minute, after which the average is calculated.
2. Measuring the speed of random read and write in 4 KB blocks (this block size is used in the overwhelming majority of real operations). The test is carried out twice - without a request queue and with a request queue with a depth of 4 commands (typical for desktop applications actively working with a branched file system). Data blocks are aligned relative to the flash drive pages. The estimation of speeds is carried out during three minutes, after which the average is calculated.
3. Determination of the dependence of the random read and write speeds during operation of a drive with 4K blocks on the depth of the request queue (in the range from one to 32 commands). Data blocks are aligned relative to the flash drive pages. The assessment of the speeds is carried out within three minutes, after which the average is calculated.
4. Determination of the dependence of the random read and write speeds when the drive is operating with blocks of different sizes. Blocks from 512 bytes to 256 KB in size are used. The depth of the request queue during the test is 4 commands. Data blocks are aligned relative to the flash drive pages. The assessment of the speeds is carried out within three minutes, after which the average is calculated.
5. Measurement of performance under a mixed multithreaded load and establishing its dependence on the ratio between read and write operations. Sequential operations of reading and writing of 128 KB blocks are used, performed in two independent streams. The ratio between read and write operations varies in 10 percent increments. The assessment of the speeds is carried out within three minutes, after which the average is calculated.
6. Investigation of SSD performance degradation when processing a continuous random write workflow. The blocks are 4 KB and the queue depth is 32 commands. Data blocks are aligned relative to the flash drive pages. The test duration is two hours, instantaneous speed measurements are carried out every second. At the end of the test, the ability of the drive to restore its performance to its original values ​​is additionally checked due to the work of the garbage collection technology and after the TRIM command has been executed.

• CrystalDiskMark 3.0.3 b
  A synthetic benchmark that provides typical performance metrics for solid-state drives as measured on a 1GB disk area “on top” of the file system. Of the entire set of parameters that can be estimated using this utility, we pay attention to the sequential read and write speed, as well as the performance of random reads and writes in 4K blocks without a request queue and with a queue of 32 commands deep.
• PCMark 8 2.0
  A benchmark based on the emulation of a real disk load, which is typical for various popular applications. On the tested drive, a single NTFS partition is created for the entire available space, and the Secondary Storage test is carried out in PCMark 8. As test results, both the final performance and the execution speed of individual test traces generated by various applications are taken into account.

⇡ Test stand

A computer with motherboard ASUS Z97-Pro, Core processor i5-4590 with integrated graphics Intel core HD Graphics 4600 and 16 GB DDR3-2133 SDRAM. SATA drives connect to the SATA 6Gb / s controller built into the motherboard chipset and work in AHCI mode... The Intel Rapid Storage Technology (RST) driver 13.1.0.1058 is used.

The volume and speed of data transfer in benchmarks are indicated in binary units (1 KB = 1024 bytes).

⇡ Test participants

• Crucial M550 256GB (CT256M550SSD1, firmware MU01)
• Intel SSD 730 480 GB (SSDSC2BP480G4, firmware L2010400);
• OCZ Vector 150 240 GB (VTR150-25SAT3-240G, firmware 1.2);
• Plextor M5 Pro Xtreme 256 GB (PX-256M5P, firmware 1.07);
• Samsung 840 Pro 256 GB (MZ-7PD256, firmware DXM06B0Q);
• Samsung 850 Pro 256 GB (MZ-7KE256, firmware EXM01B6Q);
• SanDisk Extreme II 240GB (SDSSDXP-240G, firmware R1311).

⇡ Performance

Sequential read and write operations, IOMeter

As promised by the specs, the sequential operations of the Samsung 850 Pro are limited by the SATA 6Gb / s bandwidth. In other words, here we do not have the opportunity to find out how productive the Samsung platform built on V-NAND is, but in any case, you will not find a faster sequential read or write solid-state drive with a SATA interface.

⇡ Random read and write operations, IOMeter

But in case of random reading, the power of the new Samsung flash drive can be clearly seen. We are indeed dealing with a consumer SSD offering the highest performance to date. And although the above couple of graphs only refer to random read operations, this conclusion can be transferred to most of the disk activity inherent in personal computers. It is the operations of random reads with a low depth of the request queue that make up the bulk of the load that falls on modern disks, and the Samsung 850 Pro, as we can see, is perfectly "sharpened" for it.

With random write operations, the picture is not so unambiguous. In the absence of a request queue, the Samsung 850 Pro unexpectedly falls short of the OCZ Vector 150 and Crucial M550. However, the increase in queue depth is returning everything to its place, and the Samsung 850 Pro again occupies the top line in the chart.

Let's now take a look at how the performance of the Samsung 850 Pro depends on the depth of the request queue when working with 4K blocks.

When reading with varying queue depths, the Samsung 850 Pro is by far the best SATA 6Gb / s drive on the market. When recording with a queue length of 1 or 2 commands, it is still slightly inferior to the Crucial M550 and OCZ Vector 150. However, to say that the new Samsung product is not fast enough, the language does not turn around here either.

The next pair of graphs shows the dependence of the performance of random operations on the size of the data block.

The Samsung 850 Pro works equally well with blocks of any length for any operation. In both cases, the line showing its performance, as it were, borders the indicators of other drives on top. And this means that there is not a single block size option on which the SSD under consideration would not demonstrate the best result.

Mixed Load Testing is a new addition to our SSD testing methodology. As the cost becomes cheaper, solid-state drives are no longer used as exclusively system drives and become ordinary scratch disks. In such situations, not only the refined load in the form of writing or reading falls on the SSD, but also mixed requests, when read and write operations are initiated by different applications and arrive at the same time.

However, full duplex operation for modern SSD controllers remains a significant challenge. Mixing reads and writes in the same queue slows down the speed of most consumer-grade SSDs. This was the reason for a separate study in which we are testing how SSDs perform when it is necessary to handle mixed sequential operations. The following diagram shows the most common case for desktops, when the ratio of the number of reads and writes is 4 to 1.

As follows from the above diagram, despite their three-core structure, Samsung controllers have not yet learned how to effectively work with mixed read and write operations. If a second stream initiating writing is mixed with sequential reading, then the speed of the Samsung 850 Pro drops below the level set by the Crucial M550 and OCZ Vector 150. In other words, the mixed load puts the new Samsung product, which demonstrates simply outstanding results in most tests, in a disadvantageous position ...

The following graph gives a more detailed picture of performance under a mixed load, showing the dependence of the speed of an SSD on the ratio of read and write operations to it.

The more read and write operations are mixed, the lower the performance of the Samsung 850 Pro is. The corresponding curve for this flash drive is clearly U-shaped, which indicates that the Samsung MEX controller is poorly optimized for full duplex operation. However, this behavior is the scourge of almost any modern solid-state drives for personal computers, except perhaps the OCZ Vector 150. However, the drop in performance of the Samsung 850 Pro on mixed operations reaches twice the size, which is slightly more than that of other flagship SSDs.

⇡ Degradation and recovery of performance

Observing the change in the write speed depending on the amount of information recorded on the disk is a very important experiment that allows you to understand the work of the internal algorithms of the drive. In this test, we load the SSD with a continuous stream of requests to randomly write 4K blocks and, along the way, monitor the performance that is observed. In the graph below, the dots represent the instantaneous performance measurements that we capture every second, and the black line shows the average speed observed over a 30-second interval.

As a result of the experiment, we got such an exemplary graph. Until it fills up to full capacity, the Samsung 850 Pro demonstrates a consistent and high write speed, then performance begins to decline. However, the degree of performance drop is not too high, at first the speed decreases from 90 to only 70 thousand IOPS and only then smoothly approaches the asymptote, which lies in the region of 13 thousand IOPS. This means that even in the used state, the Samsung 850 Pro performs better than other consumer SSDs, the write speed of which sags much more. A good illustration of this is the fact that during our 2-hour endurance test, we were able to record a total of 867 GB of data on the Samsung 850 Pro with 256GB. When conducting a similar test with other flagship flash drives of the same capacity, the amount of recorded information is usually about 700-720 GB.

Noteworthy is how well the Samsung 850 Pro maintains the constant write speed. Even after filling once, the scatter is almost invisible, which means the Samsung 850 Pro will fit perfectly in applications where performance consistency is required.

However, everything that is shown in the graph above is mostly an artificial situation, interesting only for studying the features of the controller, but not illustrating the behavior of an SSD in real life in personal computer... What is really important is how, after such a degradation, performance is restored to its original values. To investigate this issue, after completing the test leading to degradation of the write speed, we wait 15 minutes, during which the SSD can try to recover by itself due to garbage collection, but without the help of the operating system and the TRIM command, and measure the speed. Then the TRIM command is forcibly sent to the drive - and the speed is measured again.

CrystalDiskMark is a popular and simple benchmarking application that runs “on top” of the file system to produce repeatable results. ordinary users... And what this benchmark gives out, from a qualitative point of view, almost does not differ from the indicators that were obtained by us in the heavy and multifunctional IOmeter package. Under almost all load conditions, the Samsung 850 Pro is among the leaders, and on random read operations without a queue of requests, its performance is even noticeably higher than that of other flagship SSDs from other companies. There is only one exception - random recording without a queue of requests: here Samsung 850 Pro loses to OCZ Vector 150 and Crucial M550. However, this failure of the flash drive in question should hardly be taken to heart - such a load during typical desktop use occurs very, very rarely.

⇡ PCMark 8 2.0 Real-World Use Cases

The Futuremark PCMark 8 2.0 test suite is interesting in that it is not synthetic in nature, but rather based on how real applications work. In the course of its passage, real scenarios of disk usage in common desktop tasks are reproduced and the speed of their execution is measured. The current version of this test simulates a load taken from real game applications Battlefield 3 and World of Warcraft and software packages from Abobe and Microsoft: After Effects, Illustrator, InDesign, Photoshop, Excel, PowerPoint, and Word. The final result is calculated in the form of the average speed shown by drives when passing test tracks.

Performance in PCMark 8 is one of the most important parameters for understanding how good a particular drive is in real use... And if we rely on the indicators obtained here, then the conclusion suggests itself that the Samsung 850 Pro, which amazed us with the highest results in various synthetic tests, turns out to be completely different in real work in applications. fast SSD as it seemed at the beginning. It is not only outperformed by the high-speed 480GB version of the Intel 730, but also inferior to its predecessor, the Samsung 840 Pro. To be honest, this state of affairs seems somewhat unnatural and inconsistent with the rest of the tests. Therefore, there is a suspicion that the problem lies, for example, in some unsuccessful software optimizations that can be fixed in future firmware versions.

However, the integral result of PCMark 8 must be supplemented with the performance indicators given by flash drives when passing separate test tracks, which simulate various variants of real load. The point is that the tested flash drives behave slightly differently under different loads.

It turns out that the Samsung 850 Pro has several problematic applications at once, the results in which pull the overall PCMark 8 score down. It - Microsoft Word, Battlefield 3, Adobe photoshop when working with "heavy" images, Adobe illustrator and Adobe AfterEffects. The listed applications are characterized by the fact that the load in them is clearly heterogeneous with predominant read operations, but the write operations mixed in with them seriously reduce the read speed. We saw a similar situation in tests of mixed load, and here it manifested itself in the results of a test based on real problems.

⇡ Endurance testing

The results of testing the endurance of the drive in question are given in a separate special material "Resource tests of the SSD".

⇡ Conclusions

Recently, the emergence of each new solid state Samsung storage Is a small revolution. The company consistently introduces fundamentally new technologies and increases the productivity of its own solutions, offering more and more every time. And the Samsung 850 Pro is no exception: in fact, it turns out to be the best SATA 6Gb / s drive we've seen.

However, to announce that the novelty brought the performance of consumer SSDs to some new level, we can not. In fact, the advantage it provides is purely formal. But the Koreans are not to blame, the performance of the Samsung 850 Pro is clearly limited by the interface's capabilities. The fact that a lot of power is hidden inside it can be seen only by the speed of random reading in 4-kilobyte blocks, at which the advantage of the new item over other flagship SSDs is about 6-7 percent.

However, despite the ephemeral superiority of the new model over other flagship flash drives, Samsung did not hesitate to set frankly inflated prices on its new SSD. Modern budget SSDs like the Crucial MX100 cost almost half today. Of course, the Samsung 850 Pro has a 10-year warranty, a huge recording resource, almost eternal flash memory and excellent bundled software, but is it all worth the overpayment? Doubtful.

It turns out that the Samsung 850 Pro is not a mass product at all, but an elite offer for uncompromising enthusiasts that can fit well into a Haswell-E-based system equipped with video cards like the GeForce Titan Z, but nothing more. If we are talking about a complete set of a fairly standard desktop or mobile system, then instead of the Samsung 850 Pro, it is not difficult to choose more attractive options in terms of price-performance ratio, which are only slightly inferior in operating speed.

As a result, the Samsung 850 Pro is of the greatest interest not from a practical, but from a technological point of view, because this is the first solid-state drive in which three-dimensional flash memory has found application, which should become a ubiquitous solution over the next few years. In theory, such memory can significantly increase the speed of work and significantly reduce the cost of an SSD, but so far both of these possibilities have remained unrealized. Performance hit the SATA 6Gb / s bandwidth, and the price was high because the Samsung 850 Pro is just a pilot. That is, it is still very difficult to evaluate V-NAND at its true worth, but Samsung was able to intrigue us... And now we are looking forward to the appearance of the next SSDs from this manufacturer, built on the same memory, but at least transferred to the PCI Express bus.