We continue to deal with hard drives. And now let's talk about SDD.
What is SSD
SSD disk is a computer non-mechanical storage device consisting of memory chips and a microcontroller. Comes from the English Solid State Drive, which literally means - solid state drive.
In this definition, every word has a meaning. A non-mechanical device means that there are no mechanical parts in it - nothing moves inside, does not buzz or make noise. As a result, nothing is grinded or worn out. Since SSD drives have replaced traditional mechanical drives, this property is very important. Older drives were intimidated by vibrations during operation, solid-state drives were not.
Memory chips are used to store information. The controller on the disk allows you to receive data from memory cells and write to them, transmitting data to common interface computer, regardless of the specifics of the memory media. A giant flash drive - that's what an SSD drive is, it may seem at first glance, but only with a bunch of useless components.
What is an SSD for
In any computer, an SSD is replaced by a conventional HDD. It works faster, has a small size and does not make sounds. Fast loading speed of applications and operating system increases the comfort of working with a PC.
What is an SSD in a laptop where every watt of energy counts? Of course, first of all, it is a very economical storage medium. It is able to work with a battery charge longer. In addition, it has a very small footprint, allowing SSDs to be included in the smallest hardware configurations.
What does an SSD consist of?
A small body in which a small printed circuit board Is an SSD drive externally. Several memory chips and a controller are soldered to this board. On one side of this box there is a special SATA connector that allows you to connect an SSD drive like any other drive.
Memory chips are used to store information. Is not RAM that is in every computer. The memory in the SSD is capable of storing information even after shutdown. The memory of SSD drives is non-volatile. As with a normal disk, data is stored on magnetic platters, here the data is stored in special microcircuits. Writing and reading data is an order of magnitude faster than when working with platters of mechanical disks.
A controller on a disk is a highly specialized processor that can very efficiently distribute data in microcircuits. It also performs part of the service operations for cleaning disk memory and redistributing cells when they wear out. To work with memory, it is very important to perform service operations in a timely manner so that information is not lost.
Buffer memory is used for caching data, just like on regular disks. This is fast RAM on an SSD drive. The data is first read into the buffer memory, modified in it, and then only written to disk.
How does an SSD drive work
Principle SSD work disk is based on the specifics of the memory cells. The most common memory type is NAND. Data processing is done in blocks, not bytes. Memory cells have a limited resource of rewrite cycles, that is, the more often data is written to the disk, the faster it will fail.
Reading data is very fast. The controller determines the address of the block to be read and accesses the desired memory location. If several non-sequential blocks are read in the SDD disk, this does not affect performance in any way. There is simply a call to another block at its address.
The process of writing data is more complicated and it consists of a number of operations:
- reading a block into the cache;
- changing data in the cache memory;
- working out the procedure for erasing a block on non-volatile memory;
- writing a block to flash memory at an address calculated by a special algorithm.
Writing a block requires multiple accesses to memory locations on the SSD. An additional block cleaning operation appears before recording. In order for the flash memory cells to wear out evenly, the controller uses a special algorithm to calculate the block numbers before writing.
Block erase (TRIM) operation is performed by SSD drives when they are idle. This is done to reduce the time it takes to write a block to disk. When writing, the algorithm is optimized by removing the erasure step: the block is simply marked as free.
Operating systems execute the TRIM command on their own, which leads to the cleaning of such blocks.
Types of SSD drives
All SSD drives are divided into several types, depending on which interface they are connected to the computer.
- SATA - drives are connected to the computer using the same interface as conventional HDDs. They look like laptop drives and are 2.5 inches in size. The mSATA variant is more miniaturized;
- PCI-Express - connect like regular video cards or sound cards into the expansion slots of the computer on motherboard... They have higher performance and, most often, are installed on servers or computing stations;
- M.2 is a miniature version of the PCI-Express interface.
Modern SSDs use mainly NAND memory. By its type, they can be divided into three groups that appeared chronologically: SLC, MLC, TLC. The newer the memory became, the lower the reliability of its cells became. At the same time, the capacity grew, which helped to reduce the cost. The reliability of the disk depends entirely on the operation of the controller.
Not all SSD manufacturers make their own flash memory for their devices. Their memory and controllers are produced by: Samsung, Toshiba, Intel, Hynix, SanDisk. Few of the users have heard of a Hynix SSD. The renowned flash drive manufacturer Kingston uses Toshiba memory and controllers in its drives. Samsung itself is engaged in the development of technologies for the production of memory and controllers and equips its SSD drives with them.
SSD specifications
We have almost sorted out with SSD drives, it remains only to talk about the characteristics. So:
- Disk capacity. Usually this characteristic is indicated by a value that is not a multiple of a power of two. For example, not 256 GB, but 240. Or not 512 GB, but 480 GB. This is due to the fact that the disk controllers reserve part of the flash memory to replace the blocks that have exhausted their resource. For the user, such a substitution occurs imperceptibly and he does not lose data. If the size of the disk is 480 GB or 500 GB, then it is the flash memory on the 512 GB disk, just different controllers reserve its different volume.
- Disk speed. Almost all SSD drives have a speed of 450 - 550 MB / s. This value corresponds to the limiting speeds SATA interface through which they connect. SATA is the reason why manufacturers are not trying to massively increase read speed. The recording speed in applications is significantly lower. The manufacturer usually indicates in the characteristics exactly the write speed on a blank medium.
- The number of memory chips. The performance directly depends on the number of memory chips: the more there are, the more operations can be processed simultaneously on one disk. In one line of discs, the write speed usually increases with the growth of the disc size. This is explained by the fact that more capacious models have more memory chips.
- Memory type. More expensive and reliable MLC memory, less reliable and cheaper TLC, as well as Samsung's own development - "3D-NAND". These three types of memory are now most commonly used in storage devices. In many ways, on modern solid-state drives, the reliability of operation depends on the quality of the controller.
Solid state drives (SSD) - advantages and disadvantages
First, let's understand the definitions. Hard and solid - what's the difference?
What is a hard drive, which is also very often called HDD, hard drive, hard, screw, etc.?
HDD (English hard disk drive) is a data storage device based on the principle of magnetic recording. Information is recorded on plates covered with a layer of ferromagnet. The discs are mounted on a spindle that rotates at a very high speed (up to 15,000 rpm). In addition to the mechanical part, there is also an electronics unit, in fact, which controls the entire mechanics of the device.
The first serial hard drive was manufactured by IBM in 1956, weighed 971 kg, and had a total memory capacity of about 3.5 megabytes. History developed rapidly, and by 2011 1 terabyte became the norm for a hard drive. At the moment, there are two and even three terabyte drives.
The principle of operation of a hard disk is based on the registration of changes magnetic field near the disc head.
The main players in the hard drive market are Fujitsu, Seagate, Western Digital, Samsung, Hitachi.
The more the volume of hard disks became, the more the volume of transmitted information became. In the general mechanical structure of the hard drive lies its main drawback - a relatively low amount of data transferred per second (average models of manufacturers at the moment have an established data transfer rate of about 100-150 Mb / s). In addition, the higher the data transfer rate, the hotter the hard drive gets.
For many tasks, as well as for everyday use of a computer, these speeds are quite enough, however, with specialized use (graphics stations, professional gaming computers, computing centers, etc.), it is the hard disk that imposes significant restrictions on overall performance systems.
The first developments on the invention of a fundamentally new carrier began in the 1970s. In 1978, StorageTek introduced the first semiconductor storage device modern type thus laying the foundation for the development of solid state drives. And only in 2008, the South Korean company managed to create the first 128 GB SSD, similar to modern counterparts, which it demonstrated at an exhibition in Seoul.
Mass production was only organized in 2009. At the moment, there are 720 GB drives, the cost of which starts from 60,000 rubles, for example, the IBIS OCZ 3HSD1IBS1-720G model from the OCZ company.
So what is an SSD
Translated from English, solid-state drive means "a disk without moving parts." A solid-state drive is a storage device whose principle of operation is based on the use of rewritable microcircuits and a controller. Often users confuse terminology and call SSD hard disk... This is wrong in view of technical features solid state drives. Distinctive feature of the carrier of this type from the HDD is that when reading data from an SSD, there is no need to perform mechanical operations, all the time it takes only to transfer the address and directly the block itself. Accordingly, the faster the device and controller memory itself, the faster general access to the data.
However, the process of changing or erasing data from SSDs is not so simple. This is due to the fact that memory is written in 4 KB blocks and erased in 512 KB blocks.
When modifying blocks, the following sequence of actions occurs:
1. The block containing the changes is read into the internal buffer.
2. The necessary modification of the bytes is made.
3. The block is erased from flash memory.
4. The new location of the given block is calculated.
5. The block is written to a new location.
During the deletion of files, they are not physically deleted, but only marked by the system as deleted, however, the SSD does not know which data is user and which is deleted, and in fact, all blocks have to be processed according to the above scheme. This system leads to the fact that with a large amount of data on the disk, the total operating time increases significantly, which slows down the whole work.
SSD security and reliability
If we talk about the possibility of data recovery from SSD, then the following points can be noted:
- The data is not deleted immediately, as in the HDD, even if you overwrite the file at the top with other data.
- The data recovery process is quite time consuming, due to the fact that it is necessary to choose the correct order, combine the results, and also select the necessary algorithm that emulates the operation of the media controller.
The reliability of an SSD directly depends on the reliability of the controller and its firmware, since it is the controller that is located between the interface and the memory chips and the likelihood of its damage in case of power failure is very high.
Rules for working with solid media to extend their life cycle and increase overall speed:
- All data that changes frequently (various temporary data, swop files, etc.) can be transferred to a regular HDD.
- Disable disk defragmentation.
- Update the controller firmware periodically.
- Leaving about 20% of the disk partition permanently free will improve overall performance.
Advantages of SSDs over hard drives:
- Very high read speed of data blocks, which is actually limited only by the bandwidth of the controller interface.
- Low power consumption.
- Silence.
- Lack of mechanical parts, which leads to fewer possible breakdowns.
- Small overall dimensions.
- High temperature resistance.
Disadvantages of SSD:
- A limited number of cycles of rewriting memory cells (from 10,000 to 100,000 times). When the limit is reached, your drive will simply stop working.
- High price. Compared to the price of a 1 GB HDD (about RUB 1.6 / GB for a 1 TB HDD versus RUB 48 / GB for a 128 GB SSD).
- Low disk space compared to HDD.
- The problem of compatibility with some versions of operating systems (some operating systems simply do not take into account the specifics of solid-state media, which leads to very rapid wear of the media).
SSD companies and manufacturers you can safely trust:
Examples of models:
The average cost is 15,000 rubles.
An excellent member of the solid-state family, with a read speed of up to 355 MB / s and a write speed of up to 215 MB / s, it connects via a SATA 6 Gb / s interface.
128Gb Kingston SV100S2 / 128G SATA 2.5 "V100-Series
Average price - 6000 rubles.
A good SSD with a SATA-2 connection interface. By technical specifications from the manufacturer - write speed up to 230 MB / s, read speed up to 250 MB / s.
SSD Corsair CSSD-V64GB2-BRKT
Cheaper drive, smaller in size, with a SATA connection interface.
Average cost - 3700 rubles. It has a write speed of up to 130 MB / s and a read speed of up to 215 MB / s.
conclusions
At this stage of technology development, when solid-state media are almost 30 times more expensive than hard drives at a price per gigabyte, the feasibility of using SSDs in everyday life regular user controversial, but if you want to speed up the boot time of your operating system and brag about it to your friends, then SSD is for you. It is justified to use an SSD in mobile devices, servers with a high load on the disk system, as well as in cases where professional applications are used that require high speed data access.
A hard disk is needed to install the operating system, programs and store various user files (documents, photos, music, movies, etc.).
Hard drives differ in size, which determines the amount of data that it can store, speed, which affects the performance of the entire computer, and reliability, which depends on its manufacturer.
Regular hard drives(HDD) are large, not high speed and cost. The fastest are solid state drives(SSD), but they have a small volume and they are much more expensive. An intermediate option between the two are hybrid drives (SSHD), which have sufficient capacity, are faster than conventional HDDs and are slightly more expensive.
Western Digital (WD) hard drives are considered the most reliable. The best SSD drives are made by: Samsung, Intel, Crucial, SanDisk, Plextor. As more budget options, you can consider: A-DATA, Corsair, GoodRAM, WD, HyperX, since there are the least problems with them. And hybrid drives (SSHD) are mainly produced by Seagate.
For office computer, which is used mainly for working with documents and the Internet, a fairly common hard disk from the inexpensive WD Blue series up to 500 GB. But the optimal ones for today are 1 TB disks, since they are not much more expensive.
For a multimedia computer (video, simple games), it is better to use a 1 TB WD Blue drive as an additional one for storing files, and install a 120-128 GB SSD as the main one, which will significantly speed up the operation of the system and programs.
For gaming computer it is advisable to take an SSD with a volume of 240-256 GB, it will be possible to install several games on it.
HDD A-Data Ultimate SU650 240GB
For a more economical option for a multimedia or gaming PC, you can purchase one 1TB Seagate Hybrid Drive (SSHD), which is not as fast as an SSD, but is still slightly faster than a conventional HDD.
Seagate FireCuda ST1000DX002 1TB Hard Drive
Well, for a powerful professional PC, in addition to an SSD (120-512 GB), you can take a fast and reliable HDD WD Black of the required volume (1-4 GB).
I also recommend purchasing a quality external drive Transcend with USB interface 3.0 by 1-2 TB for the system and files important for you (documents, photos, videos, projects).
Transcend StoreJet 25M3 1 TB Hard Drive
2. Types of discs
V modern computers both classic hard disk drives (HDDs) and faster solid state drives based on memory chips (SSDs) are used. There are also hybrid drives (SSHD), which are a symbiosis of HDD and SSD.
A hard disk drive (HDD) has a large volume (1000-8000 GB), but a low speed (120-140 MB / s). It can be used both for system installation and for storing user files, which is the most economical option.
Solid state drives (SSDs) are relatively small (120-960 GB) but very fast (450-550 MB / s). They are significantly more expensive and are used to install the operating system and some programs to increase the speed of your computer.
A hybrid drive (SSHD) is simply a hard drive to which a small amount of faster memory has been added. For example, it might look like 1 TB HDD + 8 GB SSD.
3. Application of HDD, SSD and SSHD disks
For an office computer (documents, Internet), it is enough to install one regular hard disk drive (HDD).
For a multimedia computer (movies, simple games), you can put a small SSD disk in addition to the HDD, which will make the system work much faster and more responsive. As a compromise between speed and volume, you can consider installing one SSHD disk, which will come out much cheaper.
For a powerful gaming or professional computer, the best option is to install two drives - an SSD for the operating system, programs, games, and a regular hard drive for storing user files.
4. Physical sizes of disks
Desktop hard drives are 3.5 inches in size.
Solid state drives are 2.5 inches in size, just like laptop hard drives.
In a regular computer, an SSD is installed using a special mount in the case or an additional adapter.
Do not forget to purchase it if it is not included with the drive and your case does not have special mounts for 2.5 ″ drives. But now almost all modern cases have mounts for SSD drives, which is indicated in the description as internal 2.5 ″ bays.
5. Connectors of hard drives
All hard drives have an interface connector and a power connector.
5.1. Interface connector
The interface connector is the connector for connecting the disk with motherboard using a special cable (loop).
Modern hard disk drives (HDDs) have a SATA3 connector, which is fully compatible with older versions of SATA2 and SATA1. If your motherboard has old connectors, don't worry, a new hard drive can be plugged in and it will work.
But for an SSD drive, it is desirable that the motherboard has SATA3 connectors. If your motherboard has SATA2 connectors, then the SSD drive will work at half its speed (about 280 Mb / s), which, however, is still much faster than a conventional HDD.
5.2. Power connector
Modern hard disk drives (HDD) and solid state drives (SSD) have the same 15-pin SATA power connectors. If the drive is installed in a stationary computer, its power supply must have such a connector. If not, you can use a Molex-SATA power adapter.
6. Volumes of hard drives
For each type of hard disk, depending on its purpose, the amount of data that it can hold will be different.
6.1. Hard disk drive (HDD) capacity for a computer
For a computer designed for typing and Internet access, the smallest of modern hard drives- 320-500 GB.
For a multimedia computer (video, music, photos, simple games), it is desirable to have a hard drive with a capacity of 1000 GB (1 TB).
For a powerful gaming or professional computer, you may need a 2-4TB disk (be guided by your needs).
It should be noted that the computer's motherboard must support UEFI, otherwise the operating system will not see the entire disk volume over 2 TB.
If you want to increase the speed of the system, but are not ready to spend money on an additional SSD disk, then as alternative option you can consider purchasing a hybrid SSHD disk with a capacity of 1-2 TB.
6.2. Hard disk drive (HDD) capacity for laptop
If the laptop is used as an addition to the main computer, then a hard disk with a capacity of 320-500 GB will be enough for it. If the laptop is used as the main computer, it may require a 750-1000 GB hard drive (depending on the application of the laptop).
Hitachi Travelstar Z5K500 HTS545050A7E680 500GB Hard Drive
Also in the laptop you can install SSD disk which will dramatically improve the speed and responsiveness of the system or an SSHD hybrid drive that is slightly faster than a regular HDD.
Seagate Laptop SSHD ST500LM021 500GB Hard Drive
It is important to consider how thick your laptop can support. Discs with a thickness of 7 mm will fit into any model, and a thickness of 9 mm may not fit everywhere, although there are not many of them already produced.
6.3. Solid state drive (SSD) capacity
Since SSD drives are not used for storing data, when determining their required capacity, you need to proceed from how much space the operating system installed on it will take and whether you will install any other large programs and games on it.
Modern operating systems (Windows 7,8,10) require about 40 GB of space for their work and grow with updates. In addition, you need to install at least basic programs on the SSD, otherwise there will not be much sense from it. Well, for normal work the SSD should always have 15-30% free space.
For a multimedia computer (movies, simple games), the best option would be an SSD with a volume of 120-128 GB, which will allow, in addition to the system and the main programs, to install several simple games on it. Since SSD is required not only to quickly open folders, it is rational to install the most powerful programs and games on it, which will speed up their work.
Heavy modern games take up a huge amount of space. Therefore, a powerful gaming computer requires a 240-512GB SSD, depending on your budget.
For professional tasks such as video editing high quality, or to install a dozen modern games, you need a 480-1024 GB SSD, again depending on the budget.
6.4. Data backup
When choosing the volume of the disk, it is also advisable to take into account the need to create backup user files (videos, photos, etc.) that will be stored on it. Otherwise, you risk losing in one moment everything that you have accumulated over the years. Therefore, it is often more advisable to purchase not one huge disk, but two smaller disks - one for work, the other (possibly external) for backing up files.
7. Basic parameters of disks
The main parameters of disks, which are often indicated in price lists, are the spindle speed and the size of the memory buffer.
7.1. Spindle speed
The spindle has hard and hybrid disks based on magnetic platters (HDD, SSHD). Since SSDs are based on memory chips, they do not have a spindle. The speed of its work depends on the speed of rotation of the spindle of the hard disk.
The spindle of desktop hard disks is mainly 7200 rpm. Sometimes there are models with a spindle speed of 5400 rpm, which are slower.
Laptop hard drives generally have a spindle speed of 5400 RPM, which allows them to run quieter, run cooler, and use less power.
7.2. Memory buffer size
Buffer is called cache memory hard disk based on memory chips. This buffer is for speeding up work hard disk, but has little effect (about 5-10%).
Modern hard disk drives (HDD) have a buffer size of 32-128 MB. In principle, 32 MB is enough, but if the price difference is not significant, then you can take a hard disk with a large buffer size. Optimal for today is 64 MB.
8. Speed characteristics of disks
The speed characteristics common to HDD, SSHD and SSD drives include linear read / write speed and random access time.
8.1. Linear read speed
Linear read speed is the main parameter for any disk and dramatically affects the speed of its operation.
For modern hard and hybrid disks (HDD, SSHD), an average read speed closer to 150 MB / s is a good value. You shouldn't buy hard drives with a speed of 100 MB / s or less.
Solid state drives (SSD) are much faster and their read speed, depending on the model, is 160-560 MB / s. Optimal in terms of price / speed ratio are SSD drives with a read speed of 450-500 MB / s.
As for HDD disks, sellers in their prices usually do not indicate their speed parameters, but only their volume. Later in this article, I will tell you how to find out these characteristics. Everything is easier with SSD drives, since their speed characteristics are always indicated in the price lists.
8.2. Linear recording speed
This parameter is secondary after the read speed and is usually paired with it. For hard and hybrid drives (HDD, SSHD), the write speed is usually slightly lower than the read speed and is not considered when choosing a disk, since they are mainly guided by the read speed.
SSDs can have write speeds that are lower or equal to read speeds. In the prices, these parameters are indicated with a slash (for example, 510/430), where a large number means the reading speed, a smaller one means the writing speed.
Good fast SSDs have it around 550/550 MB / s. But in general, the write speed affects the computer's speed much less than the read speed. As a budget option, a slightly lower speed is allowed, but not lower than 450/350 Mb / s.
8.3. Access time
Access time is the second most important disk parameter after read / write speed. The access time especially strongly affects the speed of reading / copying small files. The lower this parameter, the better. In addition, the low access time indirectly indicates the higher quality of the hard disk drive (HDD).
A good hard disk drive (HDD) access time is 13-15 milliseconds. Values in the range of 16-20 ms are considered a bad indicator. I will also talk about how to determine this parameter in this article.
As for SSD drives, their access time is 100 times less than that of HDD drives, so this parameter is not indicated anywhere and is not paid attention to.
Hybrid disks (SSHD), due to the additional built-in flash memory, achieve lower access times than HDDs, which are comparable to SSDs. But due to the limited amount of flash memory, lower access times are only achieved when accessing the most frequently used files that have fallen into this flash memory. Usually this system files, which provides a faster computer boot speed and high responsiveness of the system, but does not drastically affect the operation of large programs and games, since they simply will not fit in the limited amount of fast memory of the SSHD disk.
9. Manufacturers of hard drives (HDD, SSHD)
The most popular hard drive manufacturers are the following:
Seagate- produces some of the fastest discs today, but they are not considered the most reliable.
Western Digital (WD)- are considered the most reliable and have a convenient color classification.
- Wd blue- low-cost general purpose disks
- WD Green- quiet and economical (often switched off)
- Wd black- fast and reliable
- Wd red- for storage systems (NAS)
- Wd purple- for video surveillance systems
- WD Gold- for servers
- WD Re- for RAID arrays
- WDSe- for scalable corporate systems
Blue - the most common drives, suitable for low-cost office and multimedia PCs. Black combines high speed and reliability, I recommend using them in powerful systems... The rest are designed for specific tasks.
In general, if you want cheaper and faster, then choose Seagate. If cheap and reliable - Hitachi. Fast and reliable - Western Digital Black.
Hybrid SSHD disks are now produced mainly by Seagete and they are of good quality.
There are discs from other manufacturers on sale, but I recommend limiting yourself to the indicated brands, since there are fewer problems with them.
10. Manufacturers of solid state drives (SSD)
Among the manufacturers of SSD drives, they have proven themselves well:
- Samsung
- Intel
- Crucial
- Sandisk
- Plextor
As more budget options, you can consider:
- Corsair
- GoodRAM
- A-DATA (Premier Pro)
- Kingston (HyperX)
11. SSD memory type
SSD drives can be built on different types of memory:
- 3 D NAND- fast and durable
- MLC- good resource
- V-NAND- average resource
- TLC- low resource
12. Speed of hard drives (HDD, SSHD)
All the parameters of SSD drives we need, such as volume, speed and manufacturer, we can find out from the seller's price list and then compare them by price.
The parameters of HDD disks can be found by the model or batch number on the manufacturers' websites, but in fact it is quite difficult, since these catalogs are huge, have a lot of incomprehensible parameters, which are called differently by each manufacturer, and also on English language... Therefore, I offer you another method that I use myself.
There is a program for testing hard drives HDTune. It allows you to define parameters such as linear read speed and access time. There are many enthusiasts who run these tests and post the results on the internet. In order to find the test results of a particular model of a hard drive, it is enough to enter its model number in the Google or Yandex image search, which is indicated in the seller's price list or on the drive itself in the store.
This is what the picture with the disk test looks like from the search.
As you can see, this picture shows the average linear read speed and random access time, which are of interest to us. Make sure that the model number in the picture matches the model number of your drive.
In addition, the graph can roughly determine the quality of the disc. An uneven graph with large jumps and high access times indirectly indicate inaccurate low-quality disc mechanics.
A beautiful cyclical or just a uniform graph without large jumps, combined with low access times, speaks of accurate, high-quality disc mechanics.
Such a drive will perform better, faster and last longer.
13. Optimal disk
So, which disk or disk configuration to choose for your computer, depending on its purpose. In my opinion, the following configurations will be the most optimal.
- office PC - HDD (320-500 GB)
- multimedia pc entry level- HDD (1 TB)
- mid-range multimedia PC - SSD (120-128 GB) + HDD (1 TB) or SSHD (1 TB)
- entry-level gaming PC - HDD (1 TB)
- Mid-Range Gaming PC - SSHD (1TB)
- gaming pc high level- SSD (240-512 GB) + HDD (1-2 TB)
- professional PC - SSD (480-1024 GB) + HDD / SSHD (2-4 TB)
14. Cost of HDD and SSD drives
In conclusion, I want to talk a little about general principles choice between more or less expensive disc models.
The price of HDD disks depends most of all on the disk capacity and slightly on the manufacturer (by 5-10%). Therefore, it is not advisable to save on the quality of HDD disks. Buy models from recommended manufacturers, albeit a little more expensive, as they will last longer.
The price of SSD drives, apart from the volume and speed, also strongly depends on the manufacturer. Here I can give a simple recommendation - choose the cheapest SSD drive from the list of recommended manufacturers, which suits you in terms of volume and speed.
15. Links
Western Digital Black WD1003FZEX 1TB Hard Drive
Western Digital Caviar Blue WD10EZEX 1 TB Hard Drive
A-Data Ultimate SU650 120GB Hard Drive
Today, most users' computers are equipped with hard drives HDD. This is a popular type that has its advantages, but SSDs are gradually replacing it from the market. Almost any modern laptop or desktop computer is sold with this kind of storage inside, but most buyers do not quite understand what is an SSD disk. Let's figure it out and define what this hard drive is, what advantages and disadvantages it has over classic and already obsolete HDD drives.
What is SSD?
If we talk in simple words then it is a computer memory device that consists of a microcontroller and microcircuits. This abbreviation stands for Solid State Drive (or Solid State Disc), which means "solid state drive" in English.
Note that this is a non-mechanical device. Unlike standard HDDs, there are no moving mechanical parts in SSD disks: a spindle, a reading head. Therefore, when this device is operating, nothing moves inside, does not rotate at great speed, does not make noise. Therefore, nothing wears out here. All of these parameters are extremely important, since they are the ones that distinguish the two technologies. The old HDD models were too sensitive to all kinds of vibrations, the new ones were not.
So, a hard disk drive stores all information not in sectors on hard platters, but directly in memory chips. A special controller allows you to write data into cells and receive them from there, transferring them to the PC interface. In fact, an SSD is a large flash drive with a huge amount of memory, but its performance or bandwidth is much higher not only the performance of a simple flash drive, but outdated HDD drives.
What is it for at all?
More efficient and efficient replacement of outdated HDD drives - this is the main goal pursued by the developers of these digital media. They are smaller, work very quickly and do not make noise during operation. On a computer that uses an SSD drive, the operating system boots up much faster, and in general, performance in different programs increases.
As for a laptop, where every watt of power counts, installing an SSD is more than justified. Here it consumes a little power, which allows laptop manufacturers to provide a higher autonomy of models. In addition, due to the small size of these devices and less heating, you can create more compact laptops and not bother too much about the implementation of a hard drive cooling system.
Composition
Outwardly, the SSD looks trite: it is a small green board with microcircuits and a controller on it, which is placed in a plastic or metal case... On one side of the case is a SATA connector through which the drive is connected to the computer's motherboard. Nearby is the power connector. Everything is just like in a regular HDD.
So, the memory chips located on the board are information storages. Unlike outdated hard drives used in HDD models, reading information from such media is much faster. Hence, GPUs get the required information for processing from the hard disk faster, which speeds up the operation of the entire system.
Controller
The on-board controller is an analogue of a processor, only it is highly specialized. Its main task is the distribution of information in microcircuits. It can also perform various service tasks: cleaning memory, redistributing cells, etc. All service tasks must be performed in a timely manner, otherwise failure to do so may lead to loss of information.
Also, the composition of the storage media for laptops and stationary PCs includes a buffer memory for caching data. It is a high-speed random access memory where data is first routed, then modified and written to disk.
Installation
Most users initially know how to install the SSD. This procedure is completely the same as installing a conventional HDD.
Unable to install this disc not right. You just need to insert it into the case, screw the assembly with screws and connect the SATA cable to the motherboard and to the media connector. The cable from the power supply is inserted into the adjacent connector. There are no cables with connectors in the system that could be mistakenly connected to the device, so there should be no problems with installation.
How it works?
It is rather difficult to explain how this device works. It is based on the specifics of the functioning of certain memory cells. Here, data processing is carried out not by bytes, but by blocks. Moreover, each cell has a certain resource of write cycles, and the more often data is written and deleted from memory, the sooner the disk will exhaust its resource and fail.
Reading data is fast. All operations are carried out through the controller, which "understands" the desired block address and accesses the required memory cell. There are times when it is necessary to read several inconsistent blocks at once, but this does not affect performance. There was no such advantage in HDD media.
The process of recording information is carried out in the following sequence:
- Reading a block into the cache.
- Changing information in the cache memory.
- Erasing a block in memory.
- Writing a new block to memory at an address that has been pre-calculated by a special algorithm.
Recording involves accessing memory cells on a digital SSD media. Before writing, the block is cleared, and in order for the disk to wear out sequentially, the controller calculates the block numbers using special algorithms.
Note that the erasure of blocks is carried out during idle operation of the medium. This shortens the time it takes to write to the disc. In this case, user intervention is not required, the system automatically executes the command to clear the blocks.
Types of SSD media
There are several types of these devices. They are divided according to the type of interface used to connect to a PC:
- SATA. SATA drives are the most common. The same connector is used to connect conventional HDDs. There is also a smaller version of this connector - mSATA.
- PCI-Express. These connectors usually connect video cards, but you can also connect a disk with the corresponding connector. This interface is located on the motherboard. When a disk is connected via PCI-Express, its performance will increase due to the higher bandwidth of this interface. Typically, SSD media for servers are connected this way.
- M.2 is another miniature option for connecting drives.
Specifications
So, you now understand what STO is. It remains only to mention the main characteristics of these devices:
- Capacity. One of important parameters, which is most often indicated by a non-multiple power of two. If HDD capacity drives was 256 or 512 GB, then the capacity of SSD devices is usually 240 or 480 GB, respectively. This is done due to the reservation of a part of the memory by the controller, which is necessary to replace the blocks that have exhausted their resource. The user does not see the replacement of blocks, and he will not lose data. That is, if the specifications indicate the volume of 480 or 500 GB, then in fact there is 512 GB available. It's just that different controllers reserve a certain amount.
- Speed. Most devices have speeds of 450-550 Mb / s. This speed is equal to the bandwidth of the SATA interface through which the drive is connected to the motherboard. However, this is quite enough for any task. After all, even the write speed in applications is lower. In the characteristics, the write speed is most often indicated, and not the bandwidth.
- The number of microcircuits. The more memory chips there are, the more operations can be processed in one unit of time. That is, the number of chips determines the performance. Typically, the write speed is faster for models with more memory. This is due to the fact that as the amount of memory grows, so does the number of chips.
- Memory type. The cheapest SSDs have TLC memory, the expensive ones have MLC memory. Samsung is using and improving its own 3D-NAND memory. The differences in the type of memory used are not visible in practice.
Conclusion
Despite the fact that such digital storage of information vaguely resembles a modern large USB flash drive, there are differences between them. In particular, these discs have a wide range of realized modern technologies, due to which a large increase in performance is achieved without loss of reliability. The speed of the entire system increases significantly when replaced old tough drive to a new solid state. Now we have finally figured out what an STS is and what are its features.
