What types of SD memory cards are there? Best SD Memory Cards (SDXC)

Having purchased a smartphone or tablet computer, you immediately want to try using a variety of interesting applications, download a cool game and much more. But to open an application for a smartphone or other device, you must first download and install it. And for this, of course, you will need a certain space in the internal memory. Music, movies, documents and other files - all this is stored on the device’s resources and sometimes takes up too much space on the built-in storage. You can expand the volume using an SD card. But not all of us know how to choose the right memory card that is not expensive and at the same time high-quality. We will also find out what classes of memory cards there are and what characteristics you should pay attention to when purchasing. This or that gadget supports specific types of equipment - if you buy another one, it simply will not work. In addition, you also need to know how much volume your smartphone or tablet supports - this is of great importance.

Types of SD cards by form factor

Previously, MultiMedia Card (MMC) was used. Then they were replaced by SD memory cards. Their physical dimensions are the same, however, they are made using completely different technologies. SD has a controller and has a security area that will not allow someone to “climb” into the system unnoticed. There is also a special switch installed that can block the ability to delete information (switched manually).

So, what types of memory cards are there and how to choose them? There are three types of SD:

• Standard SD measures 32 by 24 by 2.1 mm.
• miniSD is a little smaller - 21.5 by 20 by 1.4 mm.
• The smallest is microSD – 11 by 15 by 1 mm.

Using special adapters designed for this, any of the presented cards can be inserted into any slot that supports SD drives.

What are the classes of memory cards?

Among other things, drives differ by class. Let's figure out what a memory card class is and what does this parameter affect? So, it determines at what speed data is written. To put it in slightly different language, the higher it is, the sooner you can record data and play large video or audio recordings without loss of quality.

To help a potential buyer understand the capabilities of flash drives, the SD card association classifies them according to SD Speed ​​Class - what is it? Speed ​​characteristics: on drives, the speed is indicated based on a certain multiplier, where 1 is 150 kb/sec.

Memory cards can be manufactured in the following varieties:

• Class 2;
• Class 4;
• Class 6;
• Class 10;
• Class 16.

When choosing a memory card for a DVR or other device, you need to pay special attention to this parameter. Among other things, you need to choose a drive only from a reputable manufacturer. The fact is that many companies indicate a classification that does not correspond to speed indicators. Or it will mean not the speed of recording information, but its reading.

The type will be of no small importance for those who like to watch movies with HD resolution, the difference between them is noticeable. The higher it is, the more stable the data flows will be and there will be no slowdowns. In the documentation for the device where this or that card will be used, you should carefully read the information about the minimum speed for playing HD video.

In general, flash drives with 10th grade are considered the most popular and in demand. The speed of reading and writing information is at the most optimal level and can reach more than 10 MB/s, which is good news.

Memory card capacity

Before buying a memory card, you should check the maximum capacity your device can support. It is also recommended to pay attention to the type:

• Regular SD cards can have a capacity of no more than 4 GB;
• SDHC – up to 32 GB;
• SDXC – up to 2 TB;
• SDXC II, SDHC II, SDXC I, SDHC I - maximum available quantity.

The larger the memory card, the better, as you can store more information on it. For example, a capacity of 8 GB is enough for a thousand songs in mp3 format or 21 minutes of video recording with Full HD resolution.

Read and write speed

The speed of reading and loading information onto the card depends on its class and type.

Different types of memory cards have different data transfer speeds. What does a specific characteristic mean:

• SD – 12.5 Mb/s;
• SDHC – 12.5 Mb/s (the difference from the previous one is only in a larger volume);
• SDXC – 25 Mb/s;
• SDXC II, SDHC II, SDXC I, SDHC I - very high speed (UHS I architecture - 50 Mb/s, UHS II architecture - 156 Mb/s or 312 Mb/s).

How to determine the class of a memory card based on information exchange speed? Class characteristics:

• Class 2 – no less than 2 Mb/s;
• Class 4 – no less than 4 Mb/sec;
• Class 6 – no less than 6 Mb/sec;
• Class 10 – no less than 10 Mb/sec;
• Class 16 – no less than 16 Mb/sec.

Selecting an SD card

Despite the huge range of memory cards, it’s not difficult to figure out which one is better. The main thing is in which device the drive will be used. Standard SD format cards are most often inserted into camcorders and digital cameras. It is necessary to highlight two modifications of SD cards: SDHC and SDXC, which are characterized by increased capacity (32 GB - 2 TB). If you need a flash drive for a mobile phone or tablet, then you should look at miniSD and microSD. Despite their miniature size, these varieties are characterized by the same speed and capacity as a full-fledged SD, and differ only in an increased price.

When choosing a memory card, you also need to take into account the fact that modern formats may not be compatible with outdated devices. It is worth noting that if the gadget contains a slot for a large SD flash drive, then you can use the most ordinary microSD, provided you have a special adapter, which is almost always included with the purchase.

As for the card's capacity, it all depends on what files you plan to store on it, and in what volume. One of the most important characteristics when choosing is the speed with which it can receive and store data. For example, recording burst photos or Full HD video files on a slow card is not feasible. When playing videos, the video will “slow down” all the time. To understand how to find out the speed? You need to pay attention to the special marking - class. As was said earlier, a good memory card has a high class, and in our time it should at least be “10” for comfortable work without delays in writing and reading.

Additional information

If you are the owner of a mobile device or other gadgets, then you should know about other important parameters that need to be taken into account when choosing a memory card. Cells are provided to save all data on a flash drive. During repeated formatting and rewriting of information, these cells can “wear out”; modern drives are designed for 10,000-1,000,000 cycles of data rewriting. As practice shows, this figure can be much less. It depends on the conditions of use of the flash drive, its resistance to influences, etc. Thus, a high-quality card must be resistant to mechanical damage, high humidity, and changes in temperature conditions.

Conclusion

Choosing a high-quality memory card is not difficult. The main thing is to first study their main varieties, classes of memory cards and criteria to which you should pay especially close attention. First of all, you need to start from the device for which the drive is intended. You also need to decide on your needs that the flash drive should satisfy.

Do you know what the 10 in C, the 1 in U, and 300x mean on this card?

On mysku.ru, Vladimir Veretennikov (user Waldemarik) in a review of the MicroSD card (http://mysku.ru/blog/ebay/29690.html) wrote a whole treatise on memory card standards and notations. I took the liberty of dragging out the entire theoretical part from this review.

A little about the Secure Digital format standards:

— SD 1.0 is the very first standard, created in 1999 by SanDisk, Toshiba and Panasonic, as a direct competitor to another Memory Stick standard. This standard, in theory, implied storage capacities from 8 MB to 2 GB. File system FAT16.
— SD 1.1 is a further refinement of the standard, adopted in 2003. Among the features are an increase in capacity to 4 GB and a twofold increase in speed. File system FAT16/FAT32.
- SD 2.0 (SDHC, Secure Digital High Capacity, high capacity) - was created in 2006 to remove some of the limitations of old standards, in particular the insufficient capacity of drives. Thanks to this specification, the 4 GB limit has been removed and speed classes have been added (Class Speed ​​Rating). It is now possible to create cards with capacities from 4 to 32 GB. The changes also affected the addressing scheme and the use of the FAT32 file system.
- SD 3.0 (SDXC, Secure Digital eXtended Capacity, extended capacity) - adopted in 2009, the maximum capacity was increased to 2 TB (capacity ranges from 64 GB to 2 TB), speed class 10 was added. The updated version of this standard SD 3.01 introduces an updated data exchange protocol (UHS-I), the data exchange speed over the interface is up to 104 MB/s. File system exFAT.
- SD 4.0 (SDXC) - appeared in 2011. According to the specification, a new data exchange protocol (UHS-II) has been introduced, and a number of new contacts have been added on the cards. Data exchange speed over the interface is up to 312 MB/s. File system exFAT.

Compatibility of cards and devices of different standards:

As we can see, older SD cards are supported on all devices, the speed is limited by the speed of the card. But if you insert an SDHC or SDXC card into a device designed only for SD cards (old photo/video equipment), the device simply will not see it. All standards have only direct compatibility (support for old formats), which is why my popular SDHC card reader Kingston MCR-MRG2 (previously included with all Kingston microSDHC cards) does not see the SDXC card (second line in the photo, SDHC devices see only SD and SDHC cards). There is only one conclusion, if the smartphone/telephone/tablet/player/photo/video camera, etc. do not support SD 3.0, you should not buy SDXC cards for them. Devices simply won’t see them!!! Conversely, even in the latest device with SD 3.0 support, you can insert and use old cards without problems, but there will be speed restrictions.

A small plate of microSD card speed classes (meaning the minimum writing speed):

SD Class 2 - write speed of at least 2 MB/s
SD Class 4 - write speed of at least 4 MB/s
SD Class 6 - write speed of at least 6 MB/s
SD Class 10 - write speed of at least 10 MBs
SD Class 16 - write speed of at least 16 MB/s
UHS Speed ​​Class 1 (U1) - write speed of at least 10 MB/s, theoretical ceiling - 104 MB/s, the speed can be any (updated data exchange protocol)
UHS Speed ​​Class 3 (U3) - write speed of at least 30 MB/s (updated data exchange protocol)

Note: UHS Speed ​​Class only applies to devices that support the UHS-I interface.

Manufacturers often indicate the speed rating as a multiplier, such as 13x, 40x, 300x, etc. How can this multiplier be converted into understandable MB/s? You just need to multiply by 150, i.e. 1x = 150 KB/s = 0.15 MB/s. As a result, we have 100x=0.15*100=15 MB/s, 300x=0.15*300=45 MB/s. For those who are too lazy to calculate, here are the most popular speed ratings:

13x - 2 MB/s
26x - 4 MB/s
40x - 6 MB/s
66x - 9 MB/s
100x - 15 MB/s
106x - 16 MBs
133x - 20 MB/s
150x - 22 MB/s
200x - 30 MB/s
266x - 40 MB/s
300x - 45 MB/s
400x - 60 MB/s
600x - 90 MB/s

Note: these multipliers are indirectly related to the speed class. Often, manufacturers mark the card's read speed in this way, but the write speed can be several times lower. Always look at the speed class first, and then at the rating (multiplier).

Since our card supports the UHS-I protocol, let’s try to figure out what it is (something with Wiki):
Data bus interfaces (protocols):

UHS (Ultra High Speed) bus is a high-speed data exchange protocol introduced in version 3 of the standard. The specification requires UHS cards and controllers to be backward compatible with earlier Normal Speed ​​and High Speed ​​interfaces.
The UHS-I interface (protocol) is defined in the technical description of version 3.01. Data exchange speed via the interface is 50 MB/s or 104 MB/s. Standard pins are used, but some pin assignments are redefined to accommodate 4-bit communication.
The UHS-II interface (protocol) is defined in the technical description of version 4.00. Transfer speed - 156 MB/s or 312 MB/s. Cards of this standard contain two rows of contacts - 17 for a regular card and 16 for microSD; a 4-bit exchange mode is used.
Depending on the conductor architecture, the maximum speed over the UHS-I interface may vary. The standard allows two options: up to 50 MB/s (SDR50, DDR50) and up to 104 MB/s (SDR104). The architecture is usually indicated on the blister (packaging) of the card. In our case, this is SDR50 mode interfase, i.e. transfer speed up to 50 MB/s:

There are devices that support the UHS-I protocol, therefore, in them, a UHS-I standard card will reveal all its capabilities, in this case speed (the protocol allows data exchange speeds of up to 104 MB/s). There are also legacy devices that do not know about the UHS-I protocol (created, for example, for the second or third version of the SD 2.0 or SD 3.0 standard), so there will be some speed restrictions. A familiar situation, a high-speed UHS-I card and a cheap card reader that does not support the UHS-I protocol. The latter will greatly limit the speed, operating in High Speed ​​mode (up to 20-25 MB/s), although the card is capable of more (see photos of modes above). In more understandable language, these are like USB 2.0/3.0 standards. That is, if the flash drive worked at the limit of its capabilities of 8 MB/s on the second version, then by connecting it to the third, we will not get an increase in speed (well, insignificant). So it is here (figuratively, for comparison). This is just a “startup” for the future, because 4K and 8K are just around the corner, and at today’s speeds, you need to wait a long time to transfer such a film to the card. As they say, if your card is “tailored” to a new specification, then zer good!

A small plate according to SD standards:

If you still don’t understand the above, then this is the same thing in very simple words (you can’t figure it out without a bottle :-):
There are regular cards, and there are cards that support the UHS-I protocol (Roman numeral 1). And there are devices with or without support for the UHS-I protocol. If some element is not supported, there will be restrictions.

Here is an example - a comparison of two identical microSDHC cards, but the latter has support for the UHS-I protocol (SD 3.01 standard):

In fast card readers that support UHS-I, the first card will be limited to Normal Speed ​​or High Speed ​​modes.

Another example of a Lexar 64 GB microSDXC card (the situation is similar):

A little about marking cards.

Since there are no uniform marking standards, all manufacturers label their cards differently. The most correct labeling of cards is the one that indicates the speeds for devices that support UHS-I and for regular ones. The speed for devices supporting UHS-I is indicated by the number 1 or 3 in the letter U. The speed for conventional devices is indicated by the number inside the letter C. Additional parameters are often indicated, in the form of a read speed of 300x-500x or a speed of Up to 45 MB/s.

Example of markings:

Toshiba microSDXC card (information content 3 out of 5). As you can see, the speed class is indicated only for conventional devices (number 10 inside the letter C), i.e. speed in conventional devices is not lower than 10 MB/s. Since the card supports UHS-I (Roman numeral 1), it lacks speed class when connecting via the UHS-I interface (number 1 inside the letter U). It is not clear what the minimum recording speed is in UHS-I mode. The actual recording speed is also unknown. But there is additional information on read speed, not higher than 30 MB/s.

Next is the Samsung microSDXC card (information content 2 out of 5). As you can see, both speed class designations and the UHS-I specification icon (Roman numeral 1) are present, but there is no additional information about read speed. In devices that support UHS-I, it can vary widely, up to 104 MB/s. Here we only have a minimum write speed in any device (with/without UHS-I support) of at least 10 MB/s. The actual recording speed is unknown. Perhaps the reading speed is indicated on the packaging (blister).

More informative microSDXC Lexar (information content 3 out of 5). Both speed class designations and the UHS-I specification icon are present. As planned, 300x should mean write speed, which corresponds to 45 MB/s. Is this the real recording speed? Unfortunately no. The manufacturer is cheating again (*Up to 45MB/s read transfer, write speeds lower. Speeds based on internal testing. x=150KB/s), the “loud” numbers of 300x do not give anything, the write speed is unknown. Here 300x again means reading speed. The actual recording speed cannot be determined from the packaging.

Another microSDXC Transcend card (information content 3 out of 5). Both speed class designations and the UHS-I specification icon are present, as well as a read speed of 300x, which corresponds to 45 MB/s. Again, nothing is known about the actual write speed except that it is at least 10 MB/s.

And finally, the legendary microSDXC SanDisk (information content 3 out of 5). There is no speed class for conventional devices (the number 10 inside the letter C), although it is present on the packaging. There is also no speed rating, although the packaging shows Up to 45 MB/s (300x), in tests it shows about 45/80 MB/s for writing/reading and the price is around 3.5 kilo rubles:-(, but in a store with there is no way to know about this from the packaging.

Total: why didn’t one card receive 5 points for information content? Because manufacturers are cunning and almost always indicate the read speed (Up to 45-60 MB/s or 300x). In most cases, the write speed is important, it is the bottleneck, and it is indicated by a class that gives almost nothing (almost all cards provide a write speed of 10 MB/s). When buying in a store, you can easily run out of money and buy a regular budget card with a write speed of 10-12 MB/s (two cards with a U1 class can have different write speeds from 12 MB/s to 45 MB/s). One of the main guidelines is price. Therefore, there is only one conclusion: the information on the map/packaging does not indicate anything about the travel information and before purchasing it is better to look at speed tests on the Internet!
Before reading this text, I only knew about notation classes (a number inside the letter C) and something vague about speeds with an "x" at the end. :)

In my opinion, a very useful holiday reading. :)

For most people, microSD is just a form factor, but in reality it is not. You can easily insert any microSD card into a standard slot, but not all of them will work, since the cards differ in many ways.

Format

There are three different SD formats, available in two form factors (SD and microSD):

• SD (microSD) - drives up to 2 GB, work with any equipment;
• SDHC (microSDHC) - drives from 2 to 32 GB, work on devices supporting SDHC and SDXC;
• SDXC (microSDXC) - drives from 32 GB to 2 TB (currently maximum 512 GB), work only on devices with SDXC support.

As you can see, they are not backward compatible. Memory cards of the new format will not work on old equipment.

Volume

Support for microSDXC declared by the manufacturer does not mean support for cards of this format with any capacity and depends on the specific device. For example, the HTC One M9 works with microSDXC, but officially only supports cards up to 128 GB inclusive.

Another important point is related to the storage capacity. All microSDXC cards use the exFAT file system by default. Windows has supported it for more than 10 years, it appeared in OS X starting with version 10.6.5 (Snow Leopard), Linux distributions support exFAT, but it does not work out of the box everywhere.

High speed UHS interface

SDHC and SDXC cards can support the Ultra High Speed ​​interface, which, with hardware support on the device, provides higher speeds (UHS-I up to 104 MB/s and UHS-II up to 312 MB/s). UHS is backward compatible with earlier interfaces and can work with devices that do not support it, but at standard speeds (up to 25 MB/s).

2. Speed

Classifying the write and read speeds of microSD cards is as complex as their formats and compatibility. The specifications allow you to describe the speed of cards in four ways, and since manufacturers use them all, there is a lot of confusion.

Speed ​​class

The Speed ​​Class is associated with the minimum write speed to a memory card in megabytes per second. There are four in total:

• Class 2- from 2 MB/s;
• Class 4- from 4 MB/s;
• Class 6- from 6 MB/s;
• Class 10- from 10 MB/s.

Cards running on the high-speed UHS bus currently have only two speed classes:

• Class 1 (U1)- from 10 MB/s;
• Class 3 (U3)- from 30 MB/s.

Since the speed class designation uses the minimum entry value, theoretically a card of the second class may well be faster than a card of the fourth. Although, if this is the case, the manufacturer will most likely prefer to indicate this fact more explicitly.

Maximum speed

The speed class is quite enough for comparing cards when choosing, but some manufacturers, in addition to it, use the maximum speed in MB/s in the description, and more often than not even the write speed (which is always lower), but the read speed.

These are usually the results of synthetic tests under ideal conditions, which are unattainable in normal use. In practice, speed depends on many factors, so you should not rely on this characteristic.

Speed ​​multiplier

Another classification option is the speed multiplier, similar to the one used to indicate the read and write speed of optical discs. There are more than ten of them, from 6x to 633x.

The 1x multiplier is 150 KB/s, that is, the simplest 6x cards have a speed of 900 KB/s. The fastest cards can have a multiplier of 633x, which is 95 MB/s.

3. Objectives

Choose the right card taking into account specific tasks. The biggest and fastest is not always the best. In certain use cases, the volume and speed may be excessive.

When buying a card for a smartphone, capacity plays a bigger role than speed. The advantages of a large drive are obvious, but the advantages of high transfer speeds on a smartphone are practically not felt, since large files are rarely written and read there (unless you have a smartphone with 4K video support).

Cameras that shoot HD and 4K video are a completely different matter: both speed and volume are equally important here. For 4K video, camera manufacturers recommend using UHS U3 cards, for HD - regular Class 10 or at least Class 6.

For photos, many professionals prefer to use several smaller cards to minimize the risk of losing all the images in force majeure circumstances. As for speed, it all depends on the photo format. If you shoot in RAW, it makes sense to invest in microSDHC or microSDXC class UHS U1 and U3 - in this case they will reveal themselves fully.

4. Fakes

No matter how trivial it may sound, it is now easier than ever to buy a fake under the guise of original cards. Several years ago, SanDisk claimed that a third of SanDisk memory cards on the market were counterfeit. It is unlikely that the situation has changed much since then.

To avoid disappointment when purchasing, just use common sense. Refrain from buying from untrustworthy sellers, and beware of offers of “original” cards that are significantly lower than the official price.

Attackers have learned to fake packaging so well that sometimes it can be very difficult to distinguish it from the original. You can judge with complete confidence the authenticity of a particular card only after checking using special utilities:

• H2testw- for Windows;

If you have already experienced the loss of important data due to a memory card failure for one reason or another, then when it comes to choosing, you will most likely prefer a more expensive card from a well-known brand than an affordable “no-name” one.

In addition to greater reliability and safety of your data, with a branded card you will receive high speed and a guarantee (in some cases even lifetime).

Now you know everything you need to know about SD cards. As you can see, there are many questions that you will have to answer before purchasing a card. It's probably a best idea to have different cards for different needs. This way you can take full advantage of the equipment without exposing your budget to unnecessary expenses.

Buying a photo and video camera or another digital device, you probably paid attention to the entry in the instructions that you must use a memory card of at least N class. These recommendations should be taken seriously .

The quality of its operation depends on what class of memory card is installed in the device. On SDHC memory cards And microSD The class size is indicated on the card itself, the number is circled. In other cases, you need to consult with the seller or look in the specifications before purchasing.

Classification of memory cards.

Today there is 4 standard classes of memory cards: 2nd grade, 4th grade, 6th grade and 10th grade. You need to know that the class indicates the minimum speed of writing any information to the card. Speed ​​is measured in the well-known Megabytes per second. That is, Class 2 memory card records at a speed of at least 2 Mb/sec, 4 classes - at least 4 Mb/sec, etc. By declaring a certain speed, memory card manufacturers guarantee that the card's writing speed will be no less than the specified speed. At the same time, there may be more, which is what most often happens in practice. The card's read speed always exceeds the write speed.

Why is class rating so important for digital devices? It would seem that everything is very simple: the higher the class, the better the recording speed, and this is the card you should buy. But there are some nuances here. Tablets, phones, cameras, camcorders and other modern digital devices record at high speeds or have a small clipboard and require appropriate memory cards to function effectively. Thus, a class 2 card with the lowest write speed of 2 MB/sec is suitable for audio and video players, small devices that are not intended for active recording. The card is great for storing information. A card with 4 MB/sec recording is suitable for amateur digital cameras that shoot in JPG format and video cameras. Such cards are also used on DVRs. Yes, they include memory card And .

6th grade cards can be installed, for example, on semi-professional SLR cameras. The recording speed allows you to capture images like JPG, so RAW format. In mid-level digital cameras, they provide high quality shooting if other device parameters allow. The fastest and highest quality recording speed is provided Class 10 memory cards. They are designed to work with professional photo and video cameras and are supported by many modern car recorders. 10th grade cards allow you to record at the highest level available today Full HD video format, take and save photographic images in RAW. Cards of this type support memory capacity up to 32 GB, which is a definite plus for devices that require a large amount of memory to store information. Another big plus 10th grade cards is that they allow photographers to take burst shots with high image quality. InfoTech Company offers a wide selection memory cards in SD, SDHC, Micro SD and SDXC class 10 formats, which are suitable for use in car recorders, cameras, video cameras, etc.

You've probably seen many different memory cards and wondered: how are they all different? Many characteristics and the device manufacturer are perhaps the most important data about drives of this type. This article will discuss in detail such a property as speed class. Let's get started!

A class is a parameter that indicates the speed of information exchange between a memory card and the device in which it is installed. The higher the speed of the drive, the faster photo and video files will be recorded on it, and there will be fewer delays when opening and playing them. Since today there are as many as 3 classes, each of which can also have a different multiplier, the international organization SD Card Association (hereinafter referred to as SDA) proposed marking certain characteristics of SD memory cards directly on their case. The classes were given the name SD Speed ​​Class and currently include: SD Class, UHS and Video Class.

Thanks to this solution, anyone who wants to buy a miniature drive can simply look at its packaging in the store and get comprehensive information about its operating speed. But you must always be on guard, because some unscrupulous manufacturers, when labeling a card, may mean the speed of reading from the device, rather than writing to it, which is contrary to the SDA decision and is misleading. Before purchasing, look for test results on the Internet or check the drive directly in the store by asking a sales assistant about it. Using special software, you can check already purchased cards on your computer.

Write speed classes

SD Class, UHS, and Video Class are standards for recording on a memory card. The number indicated next to the abbreviation is the value of the minimum possible data writing speed to the device under the worst testing conditions. This indicator is measured in MB/s. The most popular is the SD Class standard and its variations, with a multiplier from 2 to 16 (2, 4, 6, 10, 16). On devices it is indicated as a letter of the Latin alphabet “C”, inside of which there is a number. This value will indicate the recording speed.

So, if you have the number 10 in the letter “C” on your card, then the speed should be at least 10 MB/s. The next stage in the development of recording speed standards is UHS. On memory cards it is designated as the letter “U” containing the Roman numeral I or III or their Arabic equivalents. Only now, unlike SD Class, the number in the symbol should be multiplied by 10 - this way you will find out the necessary characteristic.

In 2016, SDA introduced its fastest specification to date - V Class. It has speeds from 6 to 90 MB/s, depending on the multiplier. Cards that support this standard are marked with the letter “V” followed by a number. We multiply this value by 10 and voila - now we know the minimum write speed for this drive.

Important: One memory card can support several, up to all 3, speed standards, but not every device is capable of working with standards faster than SD Class.

SD Classes (C)

SD classes increase in an arithmetic progression, the step of which is 2. This is how it looks on the card body.

• SD Class 2 provides speeds of at least 2 MB/s and is designed for recording video with a resolution of 720 by 576 pixels. This video format is called SD (standard definition, not to be confused with Secure Digital - this is the name of the memory card format itself) and is used as a standard on television.
• SD Class 4 and 6 make it possible to record at least 4 and 6 MB/s, respectively, which will allow you to deal with HD and FullHD video quality. This class is intended for entry-level cameras, smartphones, game consoles and other devices.

All subsequent classes, up to UHS V Class, about which information will be given below, allow you to write data to the drive faster and more efficiently.

UHS(U)

UHS is an abbreviation of the English words “Ultra High Speed”, which can be translated into Russian as “Ultra High Speed”. To find out the minimum possible data writing speed on drives with this speed class, you need to multiply the number indicated on their case by 10.

• UHS 1 was created for high-quality video shooting in FullHD format and recording streams in real time. The promised speed of saving information to the card is at least 10 MB/s.
• UHS 3 is designed for recording 4K (UHD) video files. Used in SLR and mirrorless cameras for shooting video in UltraHD and 2K.

Video Class (V)

Abbreviated as V Class, it was introduced by the SD Card Association to designate cards optimized for recording 3D video and files with resolutions of 8K and higher. The number after the letter “V” indicates the number of MB/s written. The minimum speed for cards with this speed class is 6 MB/s, which corresponds to class V6, and the maximum class at the moment is V90 — 90 MB/s.

Conclusion

This article examined 3 speed classes that memory cards can have - SD Class, UHS and Video Class. SD Class is designed for wide application in various equipment, while other classes are intended for a narrower range of tasks. UHS will allow you to efficiently record FullHD to 4K video and live streams in real time, making it the standard for low-cost cameras. Video Class was created in order to save huge video files with 8K resolution, as well as 360° video, which predetermined the scope of its application - professional and expensive video equipment.