5/4/2019

Micro Sd Card Numbers

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As we discover every time a major manufacturer decides to release a flagship phone without a microSD slot (we're looking at you, Samsung Galaxy S6), Android enthusiasts remain passionate about our options to expand internal storage. But how well your microSD card performs depends on the class and speed of the memory card, as well as the capabilities of your phone. Here, we tell you everything you need to know to help you pick the best microSD card for your Android device.

Firstly, make sure your device supports microSD cards

Unfortunately, as we mentioned above, many smartphones don't have microSD slots and instead claim that the on-board internal storage is sufficient. And though from our perspective this seems ridiculous, we need to ensure our device has a microSD card slot.

You can inspect your device and see whether there is a microSD slot. If you need to, consult your phone's manual to open the device (or to find whether there is a microSD slot). If there is no microSD slot, well, you can't use a microSD card. If you want a phone that supports microSD take a look at the phones linked below.

What's the difference between SDHC and micro SDXC?

When buying a microSD card, you'll notice that it's either a micro SDXC or SDHC card. The difference between these two microSD formats is simply the amount of data they can store. SDHC (Secure Digital High Capacity) stores up to 32 GB of data, while SDXC (Secure Digital Extended Capacity) handles 64 GB and above.

Many lower-end devices don't support SDXC microSD cards, so it's crucial that you check your phone's compatibility before buying one. Most SDXC cards go up to 128 GB, but in March 2015, Sandisk revealed the world's first 200 GB microSD SDXC card. Coc mod apk free download.

What does 'class' mean on a microSD card?

This one's important. MicroSD cards come in several different classes - Class 2, 4, 6 and 10. While these numbers may mean nothing to you (and leave you wondering what happened to the other numbers up to 10), they do in fact simply reflect the minimum rates at which these cards sustain data transfers. Mp3 songs 320kbps download free. So a Class 2 card reads and writes data at 2 MB/s, while a Class 10 card does so at 10 MB/s. Suddenly it's not that complicated, right?

SDHC and SDXC speed classes
ClassMinimum speed
22 MB/s
44 MB/s
66 MB/s
88 MB/s
10 10 MB/s

The 'Class' number directly reflects the minimum write speed of the card. However, top-quality cards can run much faster than this, with some of the best ones out there clocking read speeds up to 95 MB/s. One such card is the SanDisk Extreme Pro, which can be picked up for $33 at Amazon.com.

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What does UHS mean on a micro SD card?

Since 2009, certain microSD cards are also UHS-1 or UHS-3-compatible. While in theory, UHS cards can reach data transfer speeds of up to 312 MB/s, you are realistically only likely to attain the minimum transfer speeds listed below, because no smartphone currently supports the UHS standard. As such, UHS will make little difference to your microSD card speed at this point.

UHS speed classes
UHS classMinimum speed
110 MB/s
330 MB/s

Will a better microSD card speed up my phone?

The most important question is whether picking one microSD card over another will improve performance on your phone, to which the short answer is 'yes'.

If you store apps and photos on your microSD card (what else would you use it for?), then a higher-speed microSD card will save photos faster, improve data transfer speeds when moving files between devices, and open apps stored on your microSD card more quickly. Note that opening apps on microSD cards may be a bit slower than if you store them on your phone's internal memory, because there's an extra layer of communication between your phone and micro SD card that needs to be carried out.

Conclusion

As you can see, there are plenty of things to consider when buying a microSD card, and hopefully the above guide will give you an idea of which one to buy. It's also worth sticking to reputable brands for microSD cards, such as SanDisk, Samsung and Kingston. Use the prices of these brands as a guidelines as well - if you see a microSD card from another company that's five times cheaper than these, you should be wary of its quality.

Do you use a microSD card? Which size and type do you use for your phone? Let us know in the comments.

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Getting yourself in a memory card muddle and not sure which card to buy? We look at memory card speeds and the fastest memory card on the market to help explain the differences so you can find out what’s the best card for you.

Not sure what the difference is between a £50 Class 2 SD and a £450 Class 10 SDHC memory card? We’ve split them up into their categories and broken down the speed jargon by translating it into real speed ratings so you can decide if a certain memory card is worth the extra money.

SD, SDHC and SDXC

As SD cards have begun to physically shrink down in size over the years, the SD card can be considered the ‘full-size’ variant. It’s typically what is used in most modern digital cameras and nearly all laptops will come equipped with an SD card reader slot.

Where things can become confusing is when you see ‘SDHC’ and ‘SDXC’. The first stands for ‘Secure Digital High Capacity’. This was initially introduced to cover SD cards with a capacity above 2GB and below 32GB. The latter stands for ‘Secure Digital eXtra Capacity’, which go far beyond 32GB in size. You can buy SDXC cards with a whopping 2TB of storage.

SD, SDHC and SDXC all physically look the same, therefore they’ll all fit in a regular SD card slot. Problems might arise depending on the device you’re looking to use them in. Older devices that pre-date SDXC’s introduction might therefore not be compatible, so be sure to check your product’s specifications. Devices are backwards compatible, so an SDXC-compatible device can use SDHC and SD cards. An SDHC-compatible device can use SDHC and SD cards, but will not be able to use SDXC cards.

MiniSD and MiniSDHC

The MiniSD was the first miniaturisation of the SD card and is around half the height of the original SD card. You can also find miniSDHC cards, which expanded storage to 4GB. Again, you’ll need to make sure your device specifically supports miniSDHC rather than just miniSD. The miniSD card never gained much traction, however, so devices that use it are relatively uncommon. Often, miniSD cards will come with an adaptor that can convert it into a full-size SD card, which makes it easier to use with laptop card readers.

MicroSD, MicroSDHC and MicroSDXC

The microSD is the smallest version. You might have also seen it referred to as TransFlash or abbreviated as a TF card. MicroSD cards, as the name implies, are physically tiny and came about predominantly to be used in smartphones that would benefit from a much smaller card.

Like the full-size SD card, there are also microSDHC and microSDXC variants that expanded the storage beyond the initial limitations. Right now, the largest microSDXC available is 128GB, which isn’t as much as the largest SDXC card but then you’re limited by the physical size of the card. When buying a microSD, microSDHC or microSDXC card you’ll usually get a full-size SD card adaptor as well. Again, SDXC-compatible devices will be backwards compatible with microSDHC and microSD cards, and microSD cards can be used in microSDHC devices.

SD card speed classes

The next area of confusion is around speed classes. These are how different SD, miniSD and microSD cards are rated in terms of read and write speeds. These are important particularly when the cards are used in camcorders or action cameras as the speed of the card will limit the video resolution and bit rate you’re able to record. High-resolution and high bit rate video requires a lot of data to be written to the card very quickly. Still cameras with high resolutions and fast burst shooting will also take modern cards to their limits.

The SD Association devised a way to standardise the speed ratings for different cards. These are defined as ‘Speed Class’ and refer to the absolute minimum sustained write speeds. Cards can be rated as Class 2 (minimum write speed of 2MB/s), Class 4 (4MB/s), Class 6 (6MB/s) or Class 10 (10MB/s). It’s important to note that these are the minimum, so it’s entirely possible a card can achieve faster speeds but these give you an impression of the least you can expect.

Many SD card manufacturers will also list a specific speed alongside the Class rating. This means a card can be Class 10 but also be listed as ‘up to 80MB/s’. The wording is important, as that’s the best you can expect but not necessarily what you’ll always achieve. You might also see a description such as ‘533x’. This refers to a multiplication of the speed of an old CD-ROM (150KB/s). So in this case 533 x 0.15 = 80MB/s (as there are 1,000KB in a MB). On any type of SD card, the Class rating is denoted by a number inside of a C symbol.

UHS Speed Class

The next rating is the UHS Speed Class. This stands for Ultra High Speed and refers to minimum sustained writing performance for recording video. UHS came about due to 4K-capable video devices needing faster write speeds.

The SD Association has two UHS Speed Classes, UHS Speed Class 1 and UHS Speed Class 3. UHS Speed Class 1 supports a minimum 10MB/s write speed, whereas UHS Speed Class 3 supports at least 30MB/s write speed. The UHS Speed Class is denoted by either a 1 or 3 inside of a bucket U symbol. As a rule of thumb, 4K-capable camcorders will usually require at least a U3 rated SD card.

UHS Bus Speed

Things get a little more confusing as UHS Speed Class-rated devices will also use one of two UHS Bus Interfaces that indicates the theoretical maximum read and write speeds. They’ll be listed as either UHS-I or UHS-II to show which interface is used. UHS-I devices have a maximum read speed of 104MB/s, whereas a UHS-II card has a maximum read speed of 312MB/s. Note, that unlike the UHS Speed Class, these are not sustained speeds.

Buying the right SD card

It might sound obvious, but the safest way to make sure you buy the correct card is to first consult your product’s user guide or specifications, at least to be sure if your device takes full-size SD or microSD cards. Checking before you buy an SD card is particularly important if your device has specific requirements, such as many 4K camcorders. These will usually explicitly state what type of memory card is required in order to record at the top resolution or bit rate. The Sony FDR-X1000V action camera, for example, clearly states that it needs a Class 10 U3 microSD card in order to record in 4K.

If you’re not recording in 4K, the speed might not be so important. A faster-rated card will still be useful if you’re using the card to expand the storage in a smartphone or laptop, as a faster read and write speed will make it more responsive. Faster cards in a still image camera will also mean being able to take more or faster photos in burst mode, as these can be written to the card far quicker. Class 10 cards are usually not much more expensive so it’s worth paying the extra.