Hard drive 2.5 inches 2 TB. Advantages of hard drives in different form factors

The reason for writing this post was to update the configuration of my main PC. In particular, after 6-7 years of operation, it would not hurt to replace the disk drives.

Actually, when changing the case, I wondered why not replace the old 3.5-inch drives with more compact 2.5-inch ones? The main goal is space saving, low noise, good performance and low heating. So can you use 2.5 "for a desktop PC?

We will try to answer these questions.

Established opinion

It just so happened historically that 3.5 ”drives are considered to be destop, i.e. focused on desktop PCs. Actually disks of this standard size are also used in servers.

2.5 ”form factor drives were originally designed for use in notebooks (laptops). Compactness was the main factor in the creation of these discs.

Over the years, 2.5-inch drives have become ubiquitous in HTPCs, game consoles, all-in-ones and compact PCs. For example, my backup Dell Optiplex 780 USFF uses just such a disk.

Over time, increased requirements for "small" drives began to be imposed, often comparable to the requirements for 3.5 ”drives.

Both 2.5 "and 3.5" currently use the SATA interface, the old IDE is finally retired. We will not consider the rest of the server solutions. Power supplies modern computers equipped with a special SATA power connector, and motherboards, even relatively old ones, have SATA ports, so there will be no problems with connection.

The main thing is to choose disks and motherboard with support for current SATA-III.

Well, let's get down to comparison?

Physical dimensions (dimensions)

As you might guess, 2.5 "drives are noticeably more compact, thinner and lighter than 3.5" drives. Large sizes of desktop disks are associated with the level of technology development at the time of their creation, namely, with the recording density. Previously, there were discs with 5 working platters, while nowadays only 2 platters are used.

The large area for the first disks was the key to increasing the amount of stored information per square centimeter of area. With the current level of technology development, the size of 3.5-inch drives is clearly redundant.

A large disc takes up more space and increases overall weight. However, you don't carry a computer with you, do you?

It's another matter if you build a system based on a system mini-ITX boards or Micro-ATX. Although most compact cases are designed to accommodate large drives, at the same time, questions may arise with the full cooling of such drives.

Large dimensions also have a negative effect on the passage of air flows. In a compact body, every centimeter matters, and in this regard, 2.5 ”CDs look much more interesting.

There is also a nuance related to the thickness of the disc. For the 2.5 "form factor, 3" standard sizes "are available at once: ultra-thin 7 mm, standard 9.5 mm and 12.5 mm.

The 7mm discs are designed for installation in ultra-thin notebooks and netbooks, where there is no physical capacity to fit a 9.5mm disc. It would seem that 2.5 mm is not a big difference, but in practice you simply cannot close the laptop lid if you install a standard disk in thin laptop... In disks with a thickness of 9.5 mm, 2 plates are used, while reading occurs from only three planes. For 12.5 mm discs, both 2 and 3 discs can be used.

When choosing a disk for a desktop PC, you can almost always close your eyes to the size when choosing a disk; in 99.5% of cases, the case design will allow you to install a disk of any thickness.

Capacity, amount of stored data

In the past, one of the key factors in favor of 3.5-inch drives was the large storage capacity.

With the development of technology hard drives the situation has changed significantly, the growth of recording density made it possible to fit up to 750 GB or even 1 TB of data on compact disks.

In turn, 3.5-inch drives still dominate the palm with available storage devices of 2 or even 4 TB. Therefore, if you are building a home NAS or you need to store very large amounts of data, your choice will most likely be obvious, and clearly not in favor of compact disks.

At the same time, as practice shows, the average user needs a 500 GB disk, provided that he uses a separate SSD for the OS.

Performance: read speed, write speed, random access

In terms of performance, not everything is as simple and unambiguous as it might seem at first glance.

Typically, "small" drives run at 5400 rpm, while "large" drives run at 7200 rpm. It would seem that a 7200 drive would work faster? However, this statement is not entirely correct. High-capacity 2.5-inch drives (500-750 GB) use high-density platters, which in practice provides them with a level of performance comparable to desktop solutions.

Often, for capacities up to 500 GB (especially 120-320 GB), a 3.5 ”drive will be faster than a regular" notebook "drive and will be cheaper.

Below is the test result from two 2.5-inch drives:

Seagate Momentus 5400.5 320 GB (ST9320320AS, 5400 RPM, 2 drives / 4 surfaces, 8 MB buffer, SATA-II).

Seagate Momentus 5400 (SpinPoint M8) 750 GB (ref.ST750LM022 HN-M750MBB, 5400 RPM, 2 disks / 3 surfaces, 8 MB buffer, SATA-II).

If you make your choice in favor of 2.5 inches, in order not to miscalculate, it is better to choose disks for 750 GB - 1 TB, if possible, for 7200 rpm.

Power consumption level

Often when comparing the two form factors, many users find the difference in power consumption not significant. For example, an average compact disc consumes about 2-4 watts in read / write mode. While desktop solutions can consume from 6 to 12 watts in active mode. Moreover, 6 W will be consumed by "green" drives with a speed of 5400.

Compared to video cards and processors capable of delivering 65-150 W TDP, this does not seem to be such a significant savings. But we should not forget about heating, because lower power consumption is almost always less heating and heat generation.

Disk heating and noise level during operation

For me personally, the level of heating and the noise produced is very important. First, higher temperatures always result in shorter operating times, always. The higher the temperature, the faster the physical wear of electronics and mechanical elements occurs. We take several hot disks and a compact case - at the output we get increased requirements for the cooling system, as a result of increased noise from CO.

Talking about the noise emitted from the HDDs themselves. You can build a configuration on the most top-end hardware, with an ultra-quiet cooling system, but your HDDs will often stand out against the general background, no matter what you do. The problem is that the noise is low-frequency and it is not as easy to remove it as it might seem, due to the need to ensure proper cooling of the drive itself.

In many ways, the noise from the HDD depends on the quality of the case, to be more precise, on its rigidity, the thickness of the metal used and the presence of damping pads.

As a rule, compact 2.5-inch drives are quieter and colder, although there are models with "chirping" heads, which are clearly audible when installed in plastic laptop cases. This noise is of a higher frequency nature than the hum from a running engine. Actually, many 3.5 ”hard drives are affected by the increased noise level emitted by a powerful motor that spins large platters at high speed.

the total cost

You have to pay for the size, in this case, for the miniature size of 2.5-inch disks you have to pay a small amount. However, in general, you need to pay extra for everything - for the amount of stored data, for the amount of cache memory, for the access speed. So the price for compactness is fully justified.

How to choose HDD for PC? 2.5 or 3.5 inches?

Now I will not consider the situation with laptops, everything is a little more complicated there due to design features (space for 1 disk). Instead, let's talk about using it in desktop configurations.

Firstly, it is 2017 and I assume in advance that you use SSD (Solid State Drive) for the system partition, since there are plenty of 60-120 GB drives available now. Even the simplest SSD will provide a significant increase in performance against the background of any, even the most productive hard disk drive (HDD). And, if when working with large files, the difference is not so noticeable, then when working with small files the HDD simply does not have a single chance.

Of course, there is also a downside to the coin. When the HDD "dies", the data can be recovered from it, but if you accidentally deleted the file, the data can be recovered. In the case of an SSD, a failed drive is easier to throw away.

When choosing a hard drive for a desktop PC, first of all, you should focus on the scope and tasks assigned. For very complex tasks such as rendering, editing, photo processing, storage of very large amounts of data - the use of standard 3.5-inch HDDs is justified to this day.

For all other tasks, there will be no significant differences between 2.5 "and 3.5". For myself, I made an unambiguous choice in favor of a compact disc, it heats up less, is not so noisy, takes up less space, and the performance level is about the same.

Many people undeservedly kick CDs for low reliability, forgetting that these drives are often used in laptops, i.e. transferred during operation, which directly affects the service life. External and portable drives always last less. I believe the MTBF will be about the same, other things being equal.

Due to the peculiarities of using "laptop" HDDs, they use a head parking system, which, when turned off, removes the heads from the disk surface. In expensive solutions, for greater protection, a gyrosensor is also used, which removes the heads in case of a fall or impact. There is such a system in desktop disks, but not in all.

The disadvantage of the parking system can be considered the peculiarities of its operation under some operating systems... Personally, after the last reinstallation, Windows 7 decided to park the heads and stop the spindle, after two weeks of such "optimization" bad sectors appeared on the WD Green disk. Coincidence? After reading thematic forums, I came to the conclusion that I'm not the only one so lucky. So, as for me, the parking is definitely disabled.

Regarding the choice of a company, for an amateur: Western digital (WD), Seagate, Toshiba and HGST (Hitachi). Samsung drives, judging by the subjective personal experience, as well as reviews on Yandex Market and other online stores, retire more often than others.

Seagate and Western Digital form the bulk of the consumer market. Toshiba and Hitachi make good drives that are in no way inferior to WD and Seagate. In general, when choosing, you must directly compare specific models, because each company has dozens of the most diverse models with very different characteristics.

About reliability. Some service centers are more likely to receive Seagate, some more often WD. This distribution is highly subjective due to the presence on the market of "unsuccessful" series, in which there were jambs in advance. It is best to look at the reviews for a specific model.

We should also mention Hitachi (HGST), the drives from this company are distinguished by increased reliability against the background of WD and Seagate. By the way, not so long ago, WD bought Hitachi, while maintaining the unit's autonomy. For this reason, WD and HGST drives are different devices.

For myself, I choose between the HGST Travelstar 7K1000 and the Seagate FireCuda SSHD 1TB 5400rpm 128MB.

When choosing a disk, pay attention to rotation speed, buffer size and connection interface. Buffer size does not affect performance as clearly as it might seem at first glance, but in general, more buffer provides better performance.

We pay a lot of attention to hard drives. This is one of those components of the system, on which the comfort of working with a PC largely depends. And if earlier we considered mainly the capabilities of 3.5-inch drives, now hard drives with 2.5 ″ platters are of no less interest - such HDDs are used not only in mobile devices, but also in monoblocks, nettops and other compact economical PCs. Having the same principle of operation, the drives of these two form factors differ markedly technical characteristics... How exactly? Let's figure it out.

Physical dimensions

The first thing you notice when looking at the drives of the two form factors is the difference in their dimensions. 2.5 "drives are much smaller than their 3.5" platter counterparts.

The amount of space occupied standard HDD, almost six times more than in the case of a 9.5 mm thick mobile hard drive. At the same time, if we calculate the capacity of the stored information per unit of volume, taking as a basis a 750-gigabyte portable disk and a 2 TB desktop drive, then the difference will be more than twofold, and not in favor of the latter (11.3 GB / cm3 and 5.1 GB / cm3).

Recording density

The diameter of the magnetic disks of both types of drives differs by 40%, while the platters of 3.5-inch hard drives have 1.8 times the working area. The same ratio remains if we consider the maximum capacity of disks used in HDD - for portable drives it is 375 GB, for desktop drives - 667 GB. From a technological point of view, the surface recording density on magnetic plates for both form factors is approximately the same. If we take into account only the formatted area available for recording user data, then for the most capacious platters it is about 330 GB per square meter. inch.

Solutions based on 2.5 "and 3.5" hard drives

Hard drives in two form factors 2.5 "and 3.5" - practical differences and applications.

Often, instead of specifying a specific form factor hard disk in inches (and a double quote denotes exactly inch), computer hardware vendors use the abbreviations SFF and LFF, abbreviations for Small Form Factor and Large Form Factor, respectively. It is not hard to guess that any (both SATA and SAS) hard drives of a smaller form factor 2.5" received designation SFF HDD, and more 3.5" - LFF HDD. It's no secret that in modern high-performance hard drives form factors 3.5 "and 2.5" manufacturers use plates of the same size - from 2.5 "HDD. Therefore, often, both the capacity and performance parameters of 2.5" and 3.5 "models of hard drives from the same manufacturer look the same. Moreover, some manufacturers have announced the discontinuation production of high-performance 3.5 "hard drives, leaving the top HDD models only in the 2.5" form factor. The availability of high-performance 3.5 "hard drives is steadily declining. Based on the realities of the modern market, manufacturers consider it economically inexpedient to use more than 2 platters inside one hard drive. For reference, in hDD form factor 2.5 "(15mm high), it is possible to install up to 3 platters, and in 3.5" HDD - up to 5 platters.

2.5 "disk

3.5 "disk

What should those consumers do who cannot or do not want (for all sorts of reasons) to use modern 2.5 "hard drives? Manufacturers offer an intermediate solution - the use of 2.5 "hard drives in a 3.5" form factor. As a 3.5 "hard drive, a regular 2.5" hard drive is offered, installed at the factory by the manufacturer in a special metal mounting case - a carriage. It should be noted that removing this hard drive from the mounting case for some manufacturers is incompatible with the warranty. Of the undoubted advantages of this design, it should be noted that the engineers of the manufacturing companies accurately calculate the dimensions and rigidity of the design, guarantee the standard arrangement of connectors and mounting holes for 3.5 "hard drives, and ensure optimal cooling of the hard drive installed inside.

If a downgrade to a smaller form factor is imminent, what will give consumers a shift to a 2.5 "hard drive form factor?
What are the differences, pros and cons of disk subsystems based on hard drives of various form factors and their scope? In two words - what's the difference?

Obviously, the smaller the hard drive is, the more such hard drives must fit inside the server.

Today, the following number of hard drives are traditionally installed in rack-mount servers:

In general (as can be seen from the table), it is possible to install in servers 2 times more hard drives of 2.5 "form factor, compared to servers of the same size, but with 3.5" hard drives.

As mentioned earlier, in the segment of enterprise-class hard drives, the maximum capacity of drives of two different form factors is the same, based on this, the use of a disk subsystem with 2.5 "bays can double the maximum total storage capacity. And even when using hard drives of low price range in which, for today, maximum volume 3.5 "hard drives are about 2 times larger than 2.5" drives, the maximum capacity of disk subsystems with bays of different form factors will be approximately the same.

As an additional bonus of using 2.5 "hard drives, it is obvious that due to the smaller dimensions (2.5" drives are less than 3.5 "drives in depth), the disk subsystem in the server takes up less space, which allows manufacturers to slightly reduce the size of servers. modern SSDs (solid state drives) are available in 2.5 "form factor and the use of 2.5" bays in the server guarantees compatibility when installing SSD-drives, and, which is especially important, in the future - with possible server upgrades.

In comparison, two 2.5 "10,000rpm (rpm) enterprise-class hard drives on a good RAID controller outperform one 3.5" drive at 15,000rpm. At the same time, the price of two 2.5 "10.000rpm 300GB discs and one 3.5" 15.000rpm 600GB disc will be approximately the same.

Such a parameter as the linear read / write speed on external tracks, in theory, should be higher for 3.5 "hard drives than for 2.5" (at the same spindle speed and at the same recording density) simply due to the physically larger platters, but in reality there are differences are negligible, as high-performance hard drives of different form factors often contain plates of the same size.

In general, the more hard disks in the server, the more power consumption (more powerful power supplies should be), and more heat dissipation (more powerful server ventilation and cooling costs should be). However, in comparison with 3.5 "models of hard drives, modern 2.5" hard drives have 2 times less power consumption (in all modes) and, as a result, less heat and cooling costs. Thus, a server with 24 2.5 "hard drives consumes less electricity and heats the surrounding space less than a server with 12 3.5" hard drives.

Great attention is always paid to the reliability of hard drives. By reducing the size (and additional engineering solutions), 2.5 "hard drives have increased vibration resistance and mechanical stress... This is confirmed by the manufacturers themselves, the mean time between failures (MTBF) of the latest 2.5 "hard drives is 2 million hours, compared to the best models 3.5 "hard drives with MTBF declared at 1.3-1.6 million hours.

And the last, despite the fact that it is not relevant in servers, but 2.5 "drives produce a little less noise during operation compared to 3.5" models.

As a result, we can summarize the pros and cons, as well as the scope of application of hard drives of various form factors.

Advantages of hard drives in different form factors

3.5 "LFF - more volume of one disk, less price per gigabyte:
• with the same recording density, more information is placed on a larger plate
• the maximum capacity of one HDD is more (in the segment of hard drives of a low price range)
• cheaper cost per gigabyte of disk space

2.5 "SFF - more capacity and performance per unit of space occupied by a server or storage system in a rack:
• 2 times more capacity storage in limited space - smaller dimensions and, as a result, higher capacity density per unit volume of space (Gigabyte / cm3) or per unit of server rack size (Gigabyte / Unit)
• higher performance of the storage system in a limited space - smaller dimensions and, as a result, higher I / O density of the disk subsystem per unit of space volume (IOPS / cm3) or per unit of server size in a rack (IOPS / Unit)
• 2 times less power consumption (in all modes) and, as a result, less heat generation and cooling costs
, modular and blade servers
• in systems with high performance disk subsystem at the expense a large number fast hard drives -
• on systems with a large number of RAID groups -
• in systems with maximum reliability of all components -
• in systems with low or limited power consumption -