Make sure you select the correct memory card for your camera.
The vast majority of cameras - at least those aimed at budding photographers and hobbyists - use SD-format memory cards to record photos and videos. Over the years they have evolved to meet the needs of more and more advanced cameras, with increasing megapixels and 4K video recording rates.
As a result, modern memory cards have many different metrics that determine their performance, which can be confusing for users unfamiliar with the terminology. In this article, before we jump into our ranking of the best SD memory cards, we provide a guide to clarify the process of choosing the best camera for your camera or laptop. Here's everything you need to know about SD cards.
Type and brand
The first thing to look at is whether your device is compatible with a particular card, and while laptops and other computers aren't too picky about this, SD card compatibility is important for cameras and camcorders.
Assuming the camera uses SD cards, it should be compatible with the two main types of cards made today, namely SDHC (Secure Digital High Capacity) and SDXC (Secure Digital eXtended Capacity).
Older cards that carry the SD mark will likely not work with modern cameras, although more are being produced as the demands of the latest technology exceed their capabilities.
The best way to check if your camera will work with an SD card is to check the specifications of the camera in the manual (or the corresponding page on the manufacturer's website).
All SDHC and SDXC memory cards have a small tab on the side that protects the contents of the card from being altered - if you slide that tab down, you won't be able to write or delete anything from the card, a useful way to protect your photos and videos, especially when the card is full. Sometimes this tab can be snagged when you insert the card into the camera. If you see an error message when trying to take a photo, remove the card and check the tab to make sure it is not locked.
Some MicroSD cards come with full-size SD adapters, so you can use them in phones and tablets, along with cameras and laptops.
Other types of SD cards come in small sizes, among them microSDXC. They are usually used in smartphones, however, they are characterized by the presence of SD adapters, which allows the use of memory cards in cameras.
Lexar and Sandisk are the dominant players in the market, although Integral, Kingston and Transcend offer completely safe alternatives that may be cheaper, while there are also more established brands like Toshiba and Samsung. Regardless of the brand you choose, buy cards from a reputable merchant, there are unscrupulous stores selling fake cards.
Capacity
—
Memory cards come in a wide range of capacities, which is reflected in their price. All memory cards with a capacity of 32 GB and below remain in the SDHC camp, while cards with a capacity of 64 GB and above are classified as SDXC. Right now, you can buy cards up to 1TB - the same as most hard drives - but they go far beyond what most people need (and what they can afford). The most common types of cards are 16 GB, 32 GB and 64 GB.
How big a map you need depends on what you are going to use it for. A user of a compact camera with a 12-megapixel sensor, for example, should have enough of a 16GB SD card if he is not going to take photos all the time. If your camera is equipped with a large sensor, however, and you are going to store files in raw format, record videos or take photos in bursts, 16 GB will not be enough very quickly.
Avoid smaller capacity cards if you tend to use burst shooting to capture moving objects, they won't be enough.
Most people find that choosing multiple medium sized cards is a better option than using one large card. This makes sense from a security standpoint - if something goes wrong, you won't lose all your photos and videos at once. It also allows you to organize your files properly. An increasing number of cameras today offer dual SD card slots, which is another reason to buy multiple cards.
Speed and performance
Most of the markings on a memory card indicate its performance when it comes to data transfer rates. We'll go over all the notation in turn.
CardsSD: Speed Class
Most modern SDHC and SDXC cards are marked with a 2, 4, 6, or 10-shaped label in an almost closed circle, this designation indicates the minimum stable write speed of this card. This mark is known as the Speed Class and allows you to judge whether your card is suitable for video recording.
The numbers indicate the speed in Mb / s. Thus, the Class 2 card has a minimum stable write speed of 2 MB / s, while the Class 4 picks up the speed to 4 MB / s and so on. In general, the faster the better, although you don't need too fast cards for standard HD video recording.
Class 10 SD cards are ideal for recording Full HD videos, but if your camera supports 4K recording, you should look for UHS (UHS Class) cards.
CardsSD: Ultra High Speed (UHS) Class
SDHC and SDXC cards usually have the numbers 1 or 3 inside a U-shaped icon. If you see any numbers in a U frame, you can be sure the card is compliant with the latest Ultra High Speed (UHS) standard.
Like the SD card class, UHS gives you an idea of the minimum guaranteed continuous write speed. So, for example, a 1 inside a U indicates a minimum sequential write speed of 10 MB / s, while a 3 indicates a speed of 30 MB / s. These cards are faster than Class 10 cards and are better suited for high-volume operations, including 4K video recording.
Attempting to record high definition video on a slow card can cause the camera to interrupt recording, and this can happen after a few seconds, so you should have an idea of what video format you are going to shoot before buying a new card.
Today, cards have appeared that comply with the UHS-I and UHS-II standards, to determine which standard the selected SD card belongs to, you can check the marking, it will be marked with the Roman "I" or "II". UHS-II cards also have an extra row of pins on the back to provide faster data transfer rates than UHS-I, but purchasing such a fast card only makes sense if you are using a relatively new camera that supports this interface. ...
Currently, most cameras support UHS-I, but only newer ones support UHS-II. However, you can benefit from their speed by using a UHS-II card reader when transferring photos to your computer.
If you do decide to buy one of these, you'll be glad to know that UHS-II cards are backward compatible with cameras that only support UHS-I, although you will lose the speed advantage inside the camera.
CardsSD:VideoSpeedClass
In addition to Speed Class and UHS Speed Class, there is a new Video Speed Class format.
SD cards of this class were designed for cameras with 8K resolution at high frame rates, so SD cards of this class are not needed by most users, since video recording in 8K resolution is not yet found in consumer products. However, they will be available to the public very soon, so you should be aware of the new classification for SD memory cards.
The good news is that this class is as easy to navigate as it is with a regular one: the SD card is marked V6, for example, which means a minimum sequential write speed of 6 MB / s. The cards are also available in V10 and V30 formats, which meet the minimum requirements for 4K video recording, and V60 and V90, which are designed for shooting in 8K resolution.
NeedCompactFlash or alternative card?
—
Not all cameras use SD cards. The CompactFlash format is still used by some professional DSLR cameras, and slots for the new CFast and XQD formats are already appearing on newer models.
These cards are labeled in a similar way as SDHC and SDXC cards, and generally have the same read speed labels, although they do not share the same classes with Speed Class cards.
In terms of read and write speeds, the fastest CompactFlash cards currently available are labeled UDMA 7. These cards have a maximum transfer rate of 167 MB / s, slightly faster than the 133 MB / s limit of the previous UDMA 6 format.
Other things to consider
Physical security
Some card manufacturers claim they are water, shock and X-ray resistant to a certain extent, and can operate in more extreme temperatures than standard cards. If you suspect that you will be working in particularly difficult conditions, or if you want extra peace of mind, you might consider them.
More professional SD cards from each manufacturer tend to include all of these options as standard. Of course, if you are going to use your camera in a particularly harsh environment, it is worth making sure that the camera, battery, and any other equipment you plan to use remains in good working order.
File recovery software
Losing photos and videos is all too easy, be it your decision or the result of file corruption. Some SD cards come with software that can potentially restore such files, although you could use third-party software for this purpose.
ReaderSD card
Check if a specific card reader needs to be paired with your SD card in order to take advantage of the fastest reading speed. Otherwise, a conventional card reader - be it a reader built into a computer or laptop - will act as a bottleneck in any file transfer operation.
Best cardsSDXC: For 4K recording and burst shooting
We tested SD card read / write speeds, both for recording stills from video, and average values subject to speed fluctuations that could lead to dropped frames. All these cards are UHS-I class, with one row of contacts on the back panel. UHS-II SD cards have a second row of pins, offering three times the theoretical speed, but require a compatible camera.
—
SanDisk's contender offered an excellent 83.3 MB / s video recording speed, and it also recorded mixed files at 56.4 MB / s, without speed dips, making the SD card one of the best on the market.
—
The Pro + SD cards delivered the fastest direct image write speed (58.2 MB / s), but not without minor speed fluctuations. Reading performance is flawless, however, as is video writing speed.
—
Kingston's fastest SD card recorded a whopping 84.1 MB / s when recording video, although transferring multiple photos returned a mediocre 42.8 MB / s, with a lot of fluctuations in speed.
Consolidated testing of 20 SDHC memory cards with a volume of 32 GB
Now, no matter what store you go to, there are a huge number of memory cards from various manufacturers on the shelves. They differ from each other in format, class and, ultimately, in the speed of reading and writing data. But how big is the difference in practice? We will check this in our new testing!
If you format the card using the standard OS utilities or in a device that does not support the SDXC standard, it will have a different file system (for example, FAT32). The SD Association warns that this will cause the card to lose compatibility with SDXC devices. Fortunately, for some card readers, cameras, etc., a driver or firmware update is sufficient.
⇡ Increase in speed: fast, faster, even faster!
Along with the volume of memory cards, the speed of data transfer also grew. In the early days of SD, it was measured in multipliers or "speeds." One multiplier (or one "speed") was equal to 150 Kbytes / s - everything is like a CD in its time. It is only in such multipliers that the maximum access speed obtained under ideal conditions, be it reading or writing, is sometimes indicated - and this is not the best option for a buyer. Therefore, SD Associations decided to put an end to this disgrace, and in 2006 (SD Specifications V. 2.0), together with SDHC cards, four speed classes were approved for them: 0, 2, 4 and 6. Each class indicated the minimum data transfer rate in decimal megabytes per second - for both reading and writing. Except for the zero grade. It includes all cards issued before the adoption of the specified specification, regardless of performance. A unified standard for marking memory cards was also approved: the figure indicating the speed class was inscribed inside the capital letter C.
Speed classes of memory cards
Alas, humanity is designed in such a way that it always lacks land, oil, minerals or the speed of memory cards. Therefore, in the next specification (SD Specifications V. 3.01 - in the same one that describes SDXC cards), the 10th speed class was introduced, with a nominal 10 MB / s (again, in decimal format), and the UHS-I bus (Ultra High Speed Version 1) that could be used with SDHC and SDXC cards. The use of this bus increases the maximum theoretical data transfer rate to 104 MB / s (in the case when this bus is supported by a card reader or other device) and does not entail any problems with backward compatibility between new cards and old readers (provided that the latter support SDHC or SDXC formats).
Memory cards that support the UHS bus are marked with the Roman numeral 1, and also the UHS bus speed markings - the numbers 1 or 3 inscribed in a capital U. UHS Class 1 is equivalent to the usual tenth SDHC speed class (10 MB / s ), and the third class of speed, as you might guess, should provide an access speed (sequential read and write) of at least 30 MB / s.
Then, in June 2011, SD specification version 4.0 appeared, describing the UHS-II bus, which should increase the maximum bandwidth up to 312 MB / s. In addition, the use of the UHS-II bus provides for an increase in contacts on the card by eight pieces. Separately, I would like to note the preservation of backward compatibility between UHS-II and UHS-I cards.
The Roman numeral II is used to label memory cards supporting the UHS-II bus.
At the time of this writing, 312 MB / s data transfer rates are still fantastic. And there are very few memory cards themselves that support the UHS-II bus, they cost like a good SSD drive, and of a larger volume. Take the Panasonic Micro P2 as an example: 32GB or 64GB, with a maximum sequential read speed of 2Gb / s. The price is about 11 or 16 thousand rubles, respectively.
UHS-II bus memory card
It turns out that over the 14 years of its existence, SD memory cards have undergone many changes and have been divided into several formats. But only readers, not cards, are backward compatible with previous formats (see diagram).
⇡ Options for marking memory cards. How not to make a mistake when buying?
Now let's briefly summarize everything that was said above. At the time of this writing, there may be two types of SD memory cards on sale: SDHC and SDXC. They differ from each other in maximum size and file system. SDHC has a maximum capacity of 32 GB and SDXC is 2 TB, although in reality it is very difficult to find an SDXC card with a capacity of more than 128 GB. We managed to find the biggest "largest" 256 GB card only from Lexar. It costs $ 399 in Amazon, but it has not been found in Russian stores.
Before proceeding to the further choice of a memory card, it is worth figuring out what capacity you need. If it is more than 32 GB, then you should go for SDXC and check all devices in which you plan to use this card for compatibility with this standard. It is especially worth checking old card readers and cameras, because modern equipment (if we are not talking about a laptop with Linux and a camera three years ago) should not have any problems with SDXC (or rather, with the exFAT file system). If your camera does not have SDXC support, then you should look on the Internet for a new firmware and a description for it - sometimes the manufacturer can add SDXC support in a new firmware. As, for example, it was done with the Pentax K-x camera.
So speed. In order to determine the approximate data transfer rate of a memory card, you need to look at its speed class and support for the UHS-I or UHS-II bus.
On some memory cards from among those that took part in our summary testing, we also found not only the marking of the usual tenth grade, but also the speed indicated in the "multipliers" - this is a normal, albeit rare, phenomenon.
The best option would be a card that has an established write or read speed, as tested by the manufacturer, on the packaging or on the front side of which. Buying such memory, you can be sure that the sequential read or write speed will be higher than the minimum allowable level for the 10th grade. And for very expensive memory cards (for example, SanDisk Extreme Pro), the declared sequential read and write speeds on packages can reach values of 90 MB / s. But in practice, memory cards with the specified speed are more expensive than others, which is quite normal - you have to pay separately for fast and tested memory. In addition, sometimes there are markings like "up to 60 MB / s" without specifying what type of data transfer this speed refers to - to read or write.
The picture below shows examples of speed class designations on memory cards. OltraMax card: just tenth grade; Transcend card: Grade 10 with UHS-I bus support and UHS speed grade 1; SanDisk: Grade 10, UHS-I, UHS-I Grade 1, and claims 95MB / s.
⇡ Test participants, specifications
Our consolidated testing involves 20 very different memory cards from various manufacturers - popular and not so popular. Among them there are both copies without the declared data transfer rate (but not lower than the 10th class), and cards with a data transfer rate of up to 90 MB / s. If the card's packaging indicated the speed, but did not say what it refers to (reading or writing), then so much the worse for a cunning manufacturer. In our table, we recorded this speed in the "read" and "write" cells with the mark "general".
Before proceeding to the description of our experimental subjects, I would like to remind you about the cost of memory cards. We have indicated two prices in the table. The first is the average retail value taken from 3DNews, and the second is obtained from other sources. Since the prices are average, the cards we have chosen in Moscow online stores can be found even cheaper than indicated in the table. Everything will depend on the total number of offers on the market, the relevance of a particular memory card and, quite likely, on the fluctuation of the dollar exchange rate over the past months.
⇡ Transcend Premium TS32GSDHC10, Premium 300x TS32GSDU1 and Ultimate 600x TS32GSDHC10U1
The trio from Transcend can serve as another illustration for the description of the marking of memory cards. On the youngest card (Premium TS32GSDHC10), only the 10th speed class is indicated, but on the other two (Premium 300x TS32GSDU1 and Ultimate 600x TS32GSDHC10U1), the 10th general and first class UHS are indicated, as well as the speed in "multipliers", which are almost equal to the speeds in MB / s indicated on the package. Something like this is done by manufacturers who want to make their cards more attractive to the buyer, because "300x" and "600x" at first glance look "larger" than 43.5 or 87.9 MB / s, respectively.
Although the fastest memory card, the Transcend Ultimate 600x TS32GSDHC10U1, has one advantage over the other test participants. The manufacturer stated that it uses MLC memory, while on the packaging (and in the specifications) of other cards it is not possible to find a word about the microcircuits used. However, the MLC (Multi-Level Cell) marking, by definition, can designate cells with both two and three (also called TLC) charge levels. Both options are used in memory cards.
⇡ Kingston Ultra SD10V / 32GB, Elite SD10G3 / 32GB and Ultimate SDA10 / 32GB
Kingston memory cards - another well-known drive manufacturer - will also be three in our testing. On the youngest card, Kingston SD10V / 32GB, only the tenth speed class is indicated, but for other cards, Kingston Elite SD10G3 / 32GB and Ultimate SDA10 / 32GB, speeds of 30 and 60 MB / s are declared for reading, respectively. For Kingston Ultimate and 35 MB / s, write speed is also stated.
⇡ SanDisk Ultra SDSDU-032G-U46, Extreme SDSDXS-032G-X46, and Extreme Pro SDSDXPA-032G-X46
SanDisk cards are a welcome exception in our test. And the thing is that all three cards of this company we use have the maximum access speed indicated. The youngest card, the SanDisk Ultra (SDSDU-032G-U46), has 30 MB / s sequential reads, while the SanDisk Extreme Pro has 95 and 90 MB / s sequential reads and writes, respectively.
⇡ ADATA ASDH32GCL10-R, ASDH32GUICL10-R and ASDH32GUI1CL10-R
ADATA is a manufacturer of storage devices of various types and purposes. The company's product line includes RAM, external hard drives, solid state drives and SD cards. It was the last three devices from ADATA that we took for the test.
Before us is an almost standard set of three cards: the simplest class 10 ADATA ASDH32GCL10-R without specifying access speeds and two more complicated cards. So, ADATA ASDH32GUICL10-R has a total speed of up to 30 MB / s, and the most pumped one, ADATA ASDH32GUI1CL10-R, has 95 MB / s for sequential reading and 45 MB / s for writing.
⇡ Silicon Power SP032GBSDH010V10, Elite SP032GBSDHAU1V10 and Superior SP032GBSDHCU1V10
Silicon Power can be called a direct competitor to ADATA, because on the official website of this company you can find almost the same range of products as on the website of the previous manufacturer.
The cheapest Silicon Power card - SP032GBSDH010V10 - only has speed class 10, while other models have speeds of 40 and 15 MB / s (Silicon Power Elite SP032GBSDHAU1V10), as well as 90/45 MB / s (Silicon Power Superior SP032GBSDHCU1V10) for reading and writing respectively.
⇡ OltraMax OM032GSDHC10, OM032GSDHC10UHS-1 and OM032GSDHC10UHS-1 95 MB / s *
OltraMax, unlike all other test participants, is practically unknown to the average consumer. But inside the packages of two fast OltraMax cards it is written that the company uses Samsung components, which is a good advertisement for the card manufacturer. The only pity is that in order to see such an advertisement, you have to buy a memory card and open the package.
The OltraMax trio is almost no different from the previous trios. The simplest and cheapest card from this manufacturer, OltraMax OM032GSDHC10, is designated only as 10th grade, the middle memory card, OltraMax OM032GSDHC10UHS-1, also cannot boast of any marks, except for 10th grade and UHS-I. But the coolest card, OltraMax OM032GSDHC10UHS-1 95 MB / s *, promises a speed of about 95 MB / s, which is very interesting.
⇡ Qumo QM32GSDHC10 and Toshiba FlashAir SD-F32AIR (BL8
The next two cards fall out of the general list a little. We received only one Class 10 drive from Qumo for testing. And Toshiba FlashAir SD-F32AIR (BL8 excels in being able to provide access to content via Wi-Fi.
Memory cards with Wi-Fi are no longer considered something unusual or innovative - many manufacturers have such models, but their small variety hints at their modest popularity. Judging by the characteristics, high speeds from Toshiba FlashAir SD-F32AIR (BL8 is not worth waiting for - this card does not even support the UHS-I memory bus. But it has Wi-Fi and even the ability to distribute wireless Internet, if you add a name to the card settings and password for access to another network
Surely you have seen many different memory cards and wondered: how are they all different? The set of specifications and the manufacturer of the device are perhaps the most important data about this type of drive. This article will discuss in detail such their property as speed class. Let's get started!
A class is a parameter that indicates the speed of information exchange between the memory card and the device in which it is installed. The higher the speed of the drive, the faster it will record photo and video files, and there will also be less brakes 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) has proposed marking certain characteristics of SD memory cards right on their case. The classes were named SD Speed Class and currently include: SD Class, UHS and Video Class.
Thanks to this solution, everyone who wants to buy a miniature drive can simply look at its packaging in the store and get comprehensive information about the speed of its operation. But you must always be on the lookout, because some unscrupulous manufacturers, when labeling a card, may mean the speed of reading from the device, and not writing to it, which is contrary to the SDA's decision and is misleading. Before buying, look for test results on the Internet or check the drive right in the store, asking a sales assistant about it. Using special software, you can check the cards you have already purchased 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 speed of writing data to the device under the worst test 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 which there is a number. This value will indicate the speed of the recording.
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 inside itself the Roman numeral I or III or their Arabic counterparts. Only now, unlike the SD Class, the number in the symbol should be multiplied by 10 - this way you will find out the required characteristic.
In 2016, SDA introduced the fastest specification to date, the V Class. It has speeds from 6 to 90 MB / s, depending on the multiplier. Cards supporting 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 faster than SD Class.
SD Classes (C)
SD classes increase in arithmetic progression, the step of which is 2. This is how it looks on the body of the card.
- SD Class 2 provides a speed of at least 2 MB / s and is designed for video recording 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 provide the ability to record at least 4 and 6 MB / s, respectively, which will allow you to already 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 in Russian can be translated as "Ultra High Speed". To find out the minimum possible speed of writing data to drives with this class of speed, you need to multiply the number indicated on their case by 10.
- UHS 1 was created for high-quality FullHD video shooting and real-time streaming recording. The promised speed of saving information to the card is at least 10 MB / s.
- UHS 3 is for recording 4K (UHD) video files. Used in SLR and mirrorless cameras for shooting video in UltraHD and 2K.
Video Class (V)
It is abbreviated as V Class and was introduced by the SD Card Association to denote cards optimized for recording 3D video and files with a resolution 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 the V6 class, and the maximum class at the moment is V90 - 90 MB / s.
Conclusion
In this article, we looked at the 3 speed classes that memory cards can have - SD Class, UHS and Video Class. SD Class is designed for wide application in various techniques, while the rest of the classes are designed for a narrower range of tasks. UHS enables you to efficiently record FullHD to 4K video and live streaming in real time, making it the standard for low-cost cameras. Video Class was created in order to store huge video files with a resolution of 8K, as well as 360 ° video, which predetermined its scope - professional and expensive video equipment.
For most people, microSD is just a form factor, but it really isn't. You can easily insert any microSD card into a standard slot, but not all of them will work, since cards differ in many ways.
Format
There are three different SD formats in total, 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 with support for SDHC and SDXC;
- SDXC (microSDXC) - drives from 32 GB to 2 TB (currently 512 GB maximum), only work on devices with SDXC support.
As you can see, they are not backward compatible. New format memory cards will not work on older hardware.
Volume
The manufacturer's declared support for microSDXC does not mean support for cards of this format with any size and depends on the specific device. For example, HTC One M9 works with microSDXC, but officially only supports cards up to and including 128GB.
One more important point is connected with the volume of storage devices. All microSDXC cards use the exFAT file system by default. Windows has been supporting it for over 10 years, in OS X it has appeared since version 10.6.5 (Snow Leopard), in Linux distributions exFAT support is implemented, but it does not work out of the box everywhere.
High speed UHS interface
I or II is added to the logo of the UHS-enabled card depending on the version SDHC and SDXC cards can support Ultra High Speed, which, when supported by hardware 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
Luca Lorenzelli / shutterstock.com Classifying the write and read speed of microSD cards is as complex as their formats and compatibility. The specs allow four ways to describe the speed of the cards, and since manufacturers use all of them, a lot of confusion arises.
Speed class
The speed class macro for ordinary cards is a number inscribed in the Latin letter C The speed class is associated with the minimum write speed to the memory card in megabytes per second. There are four of them:
- Class 2- from 2 MB / s;
- Class 4- from 4 MB / s;
- Class 6- from 6 MB / s;
- Class 10- from 10 MB / s.
By analogy with the labeling of ordinary cards, the speed class of UHS cards fits into the Latin letter U The cards operating on the high-speed UHS bus have only two speed classes so far:
- Class 1 (U1)- from 10 MB / s;
- Class 3 (U3)- from 30 MB / s.
Since the speed class designation uses the minimum record value, theoretically a second-class card may well be faster than a fourth-class card. Although, if this is the case, the manufacturer will most likely prefer to make this fact more explicit.
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 not even the write speed (which is always lower), but the read speed.
These are usually synthetic test results under ideal conditions that are unattainable with normal use. In practice, the speed depends on many factors, so you should not focus on this characteristic.
Speed multiplier
Another classification option is a 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 speed of the simplest 6x cards is 900 KB / s. The fastest cards can have a multiplier of 633x, which is 95 MB / s.
3. Tasks
StepanPopov / shutterstock.com Choose the right card based on specific tasks. The biggest and fastest is not always the best. For certain usage scenarios, volume and speed may be overkill.
When buying a card for a smartphone, volume plays a greater role than speed. The advantages of a large storage device are obvious, but the advantages of a high transfer speed 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: 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 in order to minimize the risk of losing all images in case of force majeure. As for the speed, it all depends on the photo format. If you shoot in RAW, it makes sense to invest in a microSDHC or microSDXC class UHS U1 and U3, in which case they will fully reveal themselves.
4. Counterfeits
jcjgphotography / shutterstock.com No matter how trite it may sound, buying a fake under the guise of original cards is now easier than ever. 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 that time.
Common sense is enough to avoid disappointment when buying. Refrain from buying from untrustworthy sellers, and beware of offers of "original" cards that are significantly below the official price.
Attackers have learned to counterfeit packaging so well that sometimes it can be very difficult to distinguish it from the original. It is possible to judge with complete confidence about the authenticity of a particular card only after verification using special utilities:
- H2testw- for Windows;
If you have already faced the loss of important data due to a broken memory card for one reason or another, then when it comes to choosing, you will most likely prefer a more expensive card of a well-known brand than an affordable "no-name".
In addition to the greater reliability and safety of your data, with a branded card you will receive a high speed of work and a guarantee (in some cases even a 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 the card. Perhaps the best idea is to have different cards for different needs. This way you can take full advantage of the equipment and not expose your budget to unnecessary expenses.
Almost no equipment can do without a memory card today, because all multimedia files have sufficient volume and require a lot of storage space. When choosing it, we often choose the cheaper option, wondering why some of them cost a little more.
Few of the users when buying pays attention to the class of the flash drive
It's not just about the brand, but also about the class of the memory card. Let's figure out what it means and which ones are needed for certain purposes.
This concept applies to micro, mini and full-fledged SD cards. As you might guess, their name determines the size - the smallest are used in mobile phones and tablets, the largest in photography and video equipment. We are mainly interested in compact microSDs, since they are the most popular among users.
All cards have a class that defines the guaranteed data write speed. That is, it depends on this indicator how quickly the exchange of files and information will take place when writing to an external drive.
Accordingly, the higher the class, the faster the data transfer takes place, which is the main advantage of those microSD cards that are more expensive with the same volume.
What classes are there?
The following metrics are available: 2, 4, 6, 10, 16 and Ultra-High Speed Class. Further, if your card class is 2, then the guaranteed data transfer rate is at least 2 MB / s, in the case of class 10 - at least 10 MB / s, and so on. In the case of UHS, the situation is slightly different - these drives have very high parameters and are used exclusively in those devices that support this format.
How to choose a class?
It all depends on the purpose for which you buy external memory. Pay attention to the following guidelines:
- If the card will be used exclusively for, for example, music or photos on the phone, grade 10 does not play a special role. You will only see the difference when you flush files from the computer, and it will be that at the lowest rate, the data will move a few minutes longer.
- To play music in the player, you do not need a very powerful microSD card - this does not affect the quality of work.
This indicator is of great importance when files of such type as streaming video or series of photos will be recorded on the card, in general, the following voluminous multimedia tasks:
- When recording Full HD video, you need at least 6, and best of all 10 class of memory card, so that the recording does not slow down, and you do not miss a good frame due to the fact that the device did not have time to process.
- In order to shoot high-quality objects that move, professionals buy cards with a speed of 30 MB / sec. Naturally, such equipment is more expensive, but it will reliably do its job.
- And if your goal is to make your shooting work continuous and always be ready to take a large number of shots, do not spare resources and choose drives with speeds up to 100 MB / sec.
Important! Before buying a microSD card or any other format, check the manual of your hardware device for which this part is intended - it will most likely contain the recommended parameters for the external drive. If the required class is indicated there, you can more easily navigate when buying.
Speed check
Not all microSDs indicate the class, and in some cases the declared indicator does not correspond to reality. How to check the performance of a memory card? For this, the H2testw utility has been created - quite simple and understandable for any user. After checking, the program will show you the real speed of your drive, and if, for example, the number 10 is indicated on it, and the process showed a result of about 5 MB / sec, then the manufacturer decided to deceive you.
As already mentioned, the class does not greatly affect the case when the microSD is disposed of in a phone or tablet as information storage. If you know that you often dump files and are going to be large enough, the top 10 level of the map will not hurt. This way, you can save a few minutes each time you transfer, which you can use to your advantage.
It would seem that it does not affect such a trifle as a microSD card or other format, but choosing a trusted brand when purchasing will make you more confident that the memory will work properly and without interruption. After all, the safety of your information and multimedia files directly depends on this. Therefore, it is better to pay a little extra than to lose the equipment with all the information stored on it at an unexpected moment.
Now you know what a card class is, and also when it is advisable to pay attention to it in order to get a good external memory at an optimal price.
