MicroSD cards continue to be a must-have product group for increasing storage capacity of hundreds of millions of devices, from smartphones to cameras, drones, tablets, GPS, handheld consoles and many more.
Although the main purpose of this format is still data storage and in fact there are devices that use it as the only medium, are also used to run applications and free up the internal storage of devices as can be done on Android smartphones or to run full operating systems, as we do on a single board mini-computer like the Raspberry Pi.
It should be said that microSD is the smallest variant of the Secure Digital external and removable storage standard. A standard (originally developed by SanDisk) under the responsibility of the industrial group SDA that arrived two decades ago to overcome the chaos of closed and incompatible formats that proliferated at the time. It was a great success. Although their use in mobile phones has been reduced because some manufacturers no longer support them, they are still used for multiple tasks in millions of devices.
Today we update our product guide and as we always do before offering you the best existing offers, we leave you all the keys to know them and choose the ones that best suit your needs.
MicroSD cards, characteristics
MicroSD cards are the smallest in size among the SD cards, with about extremely small dimensions of 15Ã11Ã1 mm, an area of 165 mm2 and a practically negligible weight. Surely its size has been key to increase its adoption. And its versatility, huge because they can be used directly in devices that have support for them, through internal SD adapters and also in other external, for example by using special pen drives that have microSD readers and connect to USB ports.
Although externally microSD cards are identical, there is a big difference between them and not only in storage capacity. As with other standards (see USB or Wi-Fi) those responsible have been adding a large number of features that should be known. We are going to review them all because they can be a real gibberish for the general public:
Format
This is the main division of these cards. There are three, although the only one to really value is the third one, nowadays supported by all new devices:
- microSD: The oldest. They have a capacity of up to 2 Gbytes and can be used in any microSD slot.
- microSDHC: They have a capacity from 2 to 32 GB and can be used in devices that support SDHC and SDXC.
- microSDXC: These are the most modern and the only reference currently available for purchase. Their capacity ranges from 32 Gbytes to 2 Tbytes, the maximum supported so far, although the new SD Express format that we will talk about later will greatly expand it.
Class
The ecosystem of microSD memory cards is so huge that when choosing a card we also have to take into account that the performance is sufficient for the use to which we are going to destine it. This  “Class” defines the minimum speed in Megabytes per second that the card is capable of supporting in write mode. The minimum supported write speed of each class is:
- Class 2:Â At least 2 MBps.
- Class 4:Â At least 4 MBps.
- Class 6:Â At least 6 MBps.
- Class 10:Â At least 10 MBps.
Maximum â Minimum Performance
This is the maximum and minimum speed that microSD cards can reach in data transfer and have been extended from the original ones to meet the needs of new applications such as 4K recording. The following sections should be taken into account:
The maximum reading speed (sequential) supported by a card is defined by the Ultra High Speed (UHS) specification and has two versions:
- UHS-Iwith bus speeds up to 104 Mbps
- UHS-IIÂ with bus speeds up to 312 Mbps
The minimum writing speed (sequential) supported is defined separately, with the numbers 1 or 3 inserted in a U and with two versions:
- U1:Â At least 10 MBps.
- U3:Â At least 30 MBps.
The random yield is also defined in the standard and are offered in two versions:
- A1: the original
- A2:Â Â new specification that quadruples the minimum in random reads/writes (4,000/2,000 IOPS) of the previous one.
Rated speed. Most manufacturers quote the nominal speed of their card and it is the maximum speed that in read mode they are able to achieve, expressed in MB/s.
Relative speed. It corresponds to the original transfer rate increase of the CD format (150 KBps), so you can see something like â2xâ, 4xâ and so on. A â100xâ would correspond to a speed of 15 MBps.
These last two features are not standardized, they are only used by a few manufacturers and (fortunately) are disappearing, but just in case you come across them so you know what they mean. The rest of the specifications are usually included and you will see them printed on the cards themselves, on the packaging where they are sold and on the product website.
SD Express: a new level
It is a new specification of the Secure Digital standard that has taken this format to another level in performance and capacity. To this end, the SD Express use the PCIe 3.0 interface and the NVMe v1.3 protocolprotocol, the same as those used by other storage products such as SSDs. Under PCIe, an SD Express achieves data transfer performance that will approach that of the fastest removable cards, the Compact Flash cards that are limited by price to the professional camera market.
In addition to the performance improvement it will also increase storage capacity and potentially reach 128 Tbytes. A real barbarity for SD Express cards that will initially be offered in SDUC, SDXC and SDHC formats. SDA has continued to work on this standard and has already announced version 8 with support for two PCIe lanes with an additional row of contacts and PCIe 4.0 transfer rates for a bandwidth that from the initial 985 MB/s will grow to a maximum of 3938 MB/s.
The  “Express” bus will also be available for the microSD we are concerned with in this guide. Although it will not reach the performance of the larger SD cards, the bus speed will allow for read speeds of 624 Mbytes per second. These SD Express will be able to be used for advanced photography and video tasks (handling 8K resolutions and RAW captures) so far reserved for the aforementioned Compact Flash. In terms of data storage and software execution (the most widely used in consumer applications), their level of performance will be stratospheric. Letâ¤?s hope they reach the market soon.
MicroSD cards (Prices April 2022)
With all of the above in mind we go shopping. It must be said that like all other products based on NAND flash memories the price per GB has come down a lot the last few years and if you need little storage capacity there are offers for only a few euros. The capacity will surely be the first issue to evaluate, but not the only one. If your device supports it, the minimum would be 32 Gbytes. From there, up to 1 Tbyte, you have a wide range to choose from.
As for the performancewill depend a lot on the device where you are going to use it. It has nothing to do with a GPS where we only need to extend the internal storage and little more, than if we use it to run applications from a smartphone or an operating system as in a Raspberry Pi where we will need more performance. If we use them in cameras for RAW or 4K then you will have to buy the fastest on the market.
Also note the group of “rugged” cards. They are especially dedicated to professionals or users who need memory cards with high durability and maximum resistance, protection against water, dust or X-rays from transport centers, as well as including data recovery software.
The offer is wide. All major suppliers of external and removable storage offer high reliability, speeds above the minimum and good support, up to lifetime warranty on the best models. Almost all usually include an adapter for use in SD slots and can be connected to USB ports with the appropriate adapter.
We leave you with a selection of current offers. In general, the 64, 128 and 256 GB versions are the most cost-effective in price per GB. If your device supports them, they would be the preferred choice.
Kioxia Exceria. The former Toshiba memory brand markets these MicroSDXC UHS-I, U1 cards at up to 100 MB/s with the following capacities and prices:
- 64 GB for €7.
- 128 GB for 16 euros.
- 256 GB for 39 euros.
SanDisk Ultra. MicroSDHC cards with read speed up to 120 MB/s. Class 10, U1 and A1, include an SD adapter and are distributed with the following versions and prices:
- 64 GB for 11 euros.
- 128 GB for 15 euros.
- 256 GB for 29 euros.
- 512 GB for 65 euros.
- 1 TB for 173 euros.
Samsung EVO Select. MicroSDXC UHS-I, Class 10, U3 cards up to 100 MB/s. They are shock, water, vibration and X-ray resistant. Sold with SD adapter in the following versions and prices:
- 32 GB for 11 euros.
- 64 GB for 29 euros.
- 256 GB for 42 euros.
- 512 GB for 78 euros.
Kingston Canvas Select Plus. MicroSDXC UHS-I, Class 10, U1 cards up to 100 MB/s. Shock, vibration and X-ray resistant. Sold with SD adapter in the following versions and prices:
- 32 GB for €4.
- 64 GB for 7 euros.
- 128 GB for 15 euros.
- 256 GB for 31 euros.
- 512 GB for 61 euros.
Lexar 633x. MicroSDXC UHS-I cards, Class 10, up to 100 MB/s. Sold with SD adapter in the following versions and prices:
- 32 GB for €8.
- 64 GB for 22 euros.
- 128 GB for 24 euros.
- 256 GB for 31 euros.
- 512 GB for 63 euros.
Kioxia Exceria Plus. MicroSDXC UHS-I, Speed Class U3 (V30) for 4K video recording and playback with read speeds of up to 100 MB/s and write speeds of up to 85 MB/s.
- 32 GB for €13.
- 64 GB for 20 euros.
- 128 GB for 26 euros.
- 256 GB for 48 euros.
SanDisk Extreme PRO. A Class 10, U3, V30 and A2 microSDXC with up to 170 MB/s read and 90 MB/s write data transfer. They are temperature, water, shock and X-ray resistant. They are available with / without SD adapter:
- 32 GB for 14 euros.
- 64 GB for 24 euros.
- 128 GB for 26 euros.
- 256 GB for 46 euros.
- 1 TB for 227 euros.
Our headline retailers have the selected cards and others for sale:
Notethis selection contains links from our affiliates, but none of the products included have been proposed or recommended by them or their manufacturers, but chosen at our own discretion.
