Buyer’s guide for the best micro SD cards for smartphones in 2021

Many smartphones have a microSDXC card slot, which also makes them compatible with microSD (SC) and microSDHC cards. There are several terminologies in SD card jargon that further add to the confusion. Speed ​​class C, UHS, V… Our buying guide will not only allow you to recognize the right cards, but also offers you recommendations for products of proven quality.

Best microSD cards

Smartphones are carrying more and more internal storage space, but this is not always enough. Increasingly heavy applications, photos, music, videos: so many files that quickly fill the memory of the smartphone, especially if it is an entry or mid-range model with only 32 GB or 64 GB storage. Fortunately, storage space is very often expandable via micro SD cards. But choosing them is not necessarily easy.

Micro SD, SDHC, SDXC, write and read rate, speed class: so much information that can quickly make our heads spin. In this buying guide, we will not only teach you how to understand all these criteria, but also provide you with buying recommendations so that you can find the perfect card according to your needs.

Be aware that while there are cards up to 1TB, not all capacities go with just any smartphone. So check the compatibility of your device before you start a purchase.

SanDisk Ultra microSDXC card: fast, reliable and capacities up to 512 GB

cheap SanDisk Ultra 256 GB memory card

We start with the Ultra range of memory cards from SanDisk. These are the ones that offer the best balance between capacity and price. This range is intended for those who want to be able to record Full HD videos. SanDisk Ultra memory cards are class 10 or U1, with a minimum write speed of 10MB / s.

If its transfer speed can theoretically reach 100 MB / s, this card is primarily recommended for Full HD recordings. Ideal for Android smartphones and tablets, cameras and even for the Nintendo Switch. Sandisk Ultra cards are also “A1” approved, a class defined for the speed of loading applications.

This class ensures a smooth experience with apps that load faster. Finally, note that these cards exist in capacities ranging from 16 GB to 512 GB. There is therefore something to find the version that suits you best.

SanDisk Extreme: Extreme performance, up to 1TB of storage

If you have planned to record videos in 4K, Class 10 will not be enough for you. You can thus turn to SanDisk Extreme cards which are a range above the Sandisk Ultra and Samsung Evo Plus cards. This range highlights the “V30” certification for videos. Equivalent to the U3 standard, this class offers a guaranteed minimum write speed of 30 MB / s. Enough to record videos in 4K without a hitch. In theory, their sequential speeds can go up to 160MB / s read and 90MB / s write.

This high performance memory card is ideal for Android smartphones, but also for action cameras and drones, not to mention the Nintendo Switch. Some storage capacities in this range are compatible with A2 certification, which offers good application performance for a smooth experience on Android. It is also designed and tested for foolproof redistance: extreme temperatures, water, shock and X-rays. The SanDisk Extreme is available in capacities ranging from 32 GB to 1 TB.

Samsung Evo Plus microSDX cards: comfortable in 4K, up to 512 GB of storage

Samsung’s microSDXC Evo Plus line of cards is U3 class, giving you guaranteed throughput sufficient to play and record videos in 4K UHD. They promise increased durability and speeds of up to 100MB / s read and 60MB / s write. Samsung Evo Plus memory cards also offer excellent value for money.

The 256 GB model is € 45 on Amazon. The 512 GB one is 58 €. This card is ideal for the smartphone, cameras and drones. You can just as easily use them with a Nintendo Switch. Supplied with an SD adapter, you can insert them into all devices with an SD or microSD slot.

Samsung Pro Endurance: maximum lifespan

Samsung Evo Pro Endurance

The Samsung Pro Endurance is compatible with the U1 standard which is equivalent to speed class 10. It is therefore made for Full HD video recording, but not for 4K under optimal conditions. However, you have more than enough for smooth smartphone use. Samsung is targeting users here who want endurance over time, as the name suggests. The sequential read speeds are also very good: up to 100MB / s read and 90MB / s write.

Samsung claims 25 times the endurance of the average continuous recording cycle of microSD cards. This memory card offers up to 43,800 hours of Full HD recording, which corresponds to a duration of approximately 5 years. This is also the warranty time announced by the brand. In addition, this card is very resistant and will survive temperatures between -25 ° C and 85 ° C and up to 75 hours of insertion in water. It is available in two capacities: 64 GB and 128 GB.

What is the difference between micro SD, SDHC and SDXC card?

The first thing to know is quite simply the meaning of the acronyms SD, SDHC and SDXC, the first brake when it comes to flash memory. In truth, it is very simple: these names do not indicate a different technology between each memory, but simply their maximum size.

  • micro SD : microSD or MicroSDSC (with SC for Standard Capacity) have a maximum capacity of 2 GB, but they are the most compatible, since they can be used in any device.
  • micro SDHC : these cards have a capacity between 2 and 32 GB and can only be used in devices that support micro SDHC and micro SDXC cards, but not older ones that are only compatible with micro SD cards.
  • micro SDXC : these cards have a capacity greater than 32GB and can theoretically go up to a breathtaking capacity of 2TB. Large capacity micro SDXC cards are not necessarily compatible with all devices.

So there is not really to worry about this side: you can, to simplify the matter, talk about microSD card permanently. The point on which you should pay attention, however, is the maximum capacity that your phone accepts. Of our time, almost all smartphones are compatible with the SDXC format … but the maximum supported capacities differ. This information is given in the technical sheet of your smartphone.

The different speed classes of a microSD card

Your SD card will serve as your storage memory, which means that your smartphone will have to read the information it contains as well as write new information on it. Also, its reading speed (the time it takes the system to read the information from it) and its writing speed (the time it takes the system to record new data in it) must be sufficient, so as not to slow down your use. A slow SD card is a slow smartphone after all.

There are speed classes which define in an acronym the speeds guaranteed by SD cards. The “C” classes start from 2 and evolve in increments of 2 up to 10 (except 8). The number after C corresponds to the minimum speed in MB / s.

There are 2 UHS (U) speed classes: UHS-I / UHS-II and UHS-3. Finally, the most recent acronym is V and categorizes SD cards by their minimum speed for recording videos.

Class C Minimum write speed (guaranteed) Video recording
C2 2 Mo / s SD / 480p
C4 4 Mo / s HD / 720p
C6 6 Mo / s Full HD / 1080p
C10 10 Mo / s Full HD, voire 4K
UHS class Minimum write speed (guaranteed) Video recording
UHS Class 1 (U1) 10 Mo / s Full HD, even 4K at low frames / second
UHS Class 2 (U2) 30 Mo / s Comfortable in 4K
Class V Minimum write speed (guaranteed) Video recording
Class V6 6 Mo / s Full HD
V10 10 Mo / s Full HD, even 4K at low image / second
V30 30 Mo / s Comfortable in 4K
V60 60 Mo / s 4K at over 60 fps
V90 90 Mo / s Comfortable even in 8K
MicroSD speed classes

New classes of application performance

The new application performance classes provide an indication of performance for applications such as Android smartphones and tablets. With these new standards, you can record directly to the card, run applications or games at high speeds.

Operating systems process data at random intervals, which involves input / output per second (IOPS). IOPS are therefore important when talking about the performance of SD cards on smartphones. High IOPS equals low latency. For now, there are classes for application performance: A1 and A2.

All correspond to a minimum speed of 10MB / s but the IOPS performance differs. Whether your micrSDXC card is A1 or A2 approved, this means that it is optimized for smooth applications.

Class A Minimum write speed (guaranteed) Minimum random read Minimum random write
A1 10 Mo / s 1500 IOPS 500 IOPS
A2 10 Mo / s 4000 IOPS 2000 IOPS

So much for our guide to buying the best microSD cards. Finally, we invite you to consult our file which explains how to choose the right microSD card.

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