What are microSD Express cards and why do they matter?

If you're wondering what microSD Express cards are and why everyone's talking about them, especially those who are going to give the jump to Switch 2Here's the full explanation. We are witnessing a huge evolution in external storage. In a micro format, this completely changes the performance you'd expect from such a tiny card. And yes, there's a direct impact on loading times, compatibility, pricing, and availability.

Nintendo's decision to allow expansion of its new console only with microSD Express has sparked debate. You will not be able to reuse your original Switch UHS-I microSD cardHowever fast and reliable it may be, there are compelling technical reasons for this. In return, transfer speeds arrive that, while not reaching those of a SSD Internally, they make a leap that is very noticeable in complex games.

What exactly are microSD Express cards?

MicroSD Express is the micro format adaptation of SD Express, the standard that the SD Association publicly presented in Barcelona during MWC 2019. Its main difference compared to traditional microSD cards It doesn't rely on the classic UHS interface: it uses PCIe 3.1 and the NVMe 1.3 protocol, the same combination used by modern PC SSDs. To achieve this, this format adds a second row of pins to the card, without increasing its size.

This change in data bus represents a before and after in performance. Full-size SD Express cards achieve theoretical speeds of up to 3.940 MB/s According to the SD 8.0 specification, in the microSD world, the maximum speeds are lower due to physical limitations, but they are still impressive. The SD Association reports peak speeds of 985 MB/s for microSD Express, which is already several times faster than the fastest UHS-I cards.

Another, less obvious advantage is energy consumption. The Association's own technical materials explain that this standard can offer lower energy expenditure for use in devices like mobile phones or cameras, which always contributes to battery life. Furthermore, microSD Express comes in three capacity variants: microSDHC Express, microSDXC Express, and microSDXC Express, covering everything from modest to enormous sizes.

PCIe, NVMe and lanes: why they affect speed

To understand why not all microSD Express cards perform the same, it is helpful to understand two concepts from the world of computers. PCIe is the highway that data travels on. between the CPU and peripherals, and is organized by version and lanes. The more lanes allowed and the more modern the PCIe version, the greater the available bandwidth.

In a specific device, the manufacturer decides which version of PCIe to enable (for example, 3.0 or 4.0) and how many lanes to dedicate to each peripheral. There are a limited number of lanes to allocate.Because the GPU, Wi-Fi, and internal SSD also need them. This combination determines the actual speed limit. In theory, and depending on the bus, the total speed can range from about 985 MB/s to nearly 3.940 MB/s, although microSD cards rarely reach that latter extreme.

Even if the bus allows a lot, a microSD Express will not equal an internal SSD for an architectural reason. A micro SD card has fewer NAND chips working in parallel.Therefore, some of the interlacing that boosts performance in an SSD is lost. It's a physical limitation of the form factor, and there's no magic solution.

Theoretical speeds and real-world speeds

The actual figures announced by manufacturers help to manage expectations. SanDisk markets an Express microSD card that claims up to 880 MB/s reading and 650 MB/s writingThese are very high numbers for this format, although below what you would see in a top-of-the-range internal NVMe SSD.

How does that compare to a standard UHS-I microSD card found in consoles, mobile phones, and cameras? The UHS-I interface remains at a maximum of 104 MB/s At the bus level, and although some premium UHS-I cards boast advertised sequential read speeds, the practical ceiling for sustained write speeds is much lower than on Express. In other words, the bandwidth increase is several times greater.

Even in the worst compatible scenario, the difference compared to any microSD UHS-I from your old Switch is huge. SD Express will not make the external card appear as an internal SSDHowever, it does reduce bottlenecks and brings the experience much closer to the system's main storage, especially during long loads or streaming of heavy textures.

Speed ​​classes: C, U, V… and the new Express indicator

The microSD world has gone through different ways of labeling performance. First came Speed ​​Class with a C; then UHS Speed ​​Class, with U1 or U3; and later Video Speed ​​Class, with a V followed by a number. All indicate minimum sustained writing timeC10 is equivalent to 10 MB/s, U3 to 30 MB/s, and so on in the V family.

With microSD Express comes a new logo. The symbol is a stylized EX or E, sometimes accompanied by a number. That mark also refers to sustained lows In terms of write speeds, official ranges are between 150 and 600 MB/s. As always, some manufacturers publish higher peaks, but the actual speed will depend on the card reader controller and the card itself.

Looking back, it's been a long journey: The first SD cards ran at 12,5 MB/sThen came the high speed of 25 MB/s, and with UHS III, speeds reached 312 MB/s. The arrival of SD Express multiplies these values, and its micro version captures the most significant portion of this improvement without reaching the full-size card's maximum speed.

Switch 2 and the microSD Express requirement

Nintendo has indicated that its new console only accepts expansion via microSD Express. This means you won't be able to use your original Switch card. and just keep playing. It might be a nuisance if you already had several microSD cards, but the decision aligns with the system's technical ambitions.

The reasons are clear. The Switch 2 promises more complex and demanding games, such as Cyberpunk 2077 on Switch 2, some of them coming from platforms that require high storage bandwidth. To put things in context, Sony requires 5.500 MB/s read speed. at least for the SSD PlayStation 5. Although the Switch 2 doesn't match that figure, it's clear that a microSD UHS-I card would fall short in situations where the game loads a lot of data in real time.

In addition, Nintendo has updated the system's internal storage, abandoning eMMC to switch to UFS. Early demos point to significant improvements in loading timesSome have measured up to 35 percent less data transfer on fast trips, according to Polygon, and up to three times less on initial load times, according to Digital Foundry. Part of the credit goes to the storage capacity; part to a more powerful CPU and GPU that decompress data more efficiently.

If the internal level increases, the expansion must follow. Implementing microSD Express prevents future games from being held back. due to slow cards, and allows developments that rely on content streaming to use the external card without a dramatic penalty.

Compatibility and backward compatibility: what you should know

On paper, microSD Express is backward compatible with the previous ecosystem: Express cards can operate in UHS-I mode On older systems that don't support PCIe, you'll experience reduced speed. But be aware, standard backward compatibility doesn't mean a specific product will accept any card.

In the case of Switch 2, Nintendo restricts expansion to microSD Express by design. It is a limitation chosen by the host manufacturerThis is not due to a technical limitation of the standard. So keep this in mind: even if your UHS-I microSD card is high-end, the console will not allow you to use it to install games and data.

To complete the context, this evolution can be interpreted as a response to alternatives that arose on their own. Huawei It boosted NM Cards with an even smaller formatAnd SD Express, in its two flavors, SD and microSD, reinforces the value of sticking to the SD standard with a strong leap in performance and efficiency.

Speeds, bottlenecks, and physical limits

It's worth remembering that not everything is about the bus. Performance also depends on the card's controller.This depends on the number and quality of NAND chips, as well as the firmware. MicroSD cards have fewer parallel channels than an M.2 SSD for PCs, so the interleaving of writes and reads doesn't scale as much.

That's why you'll see marked differences between models even within microSD Express. The most frequently repeated realistic figure is around 800-900 MB/s for reading. For high-end devices, it's far from the theoretical limit of a full-size SD card with PCIe and more lanes. This is normal, and even so, the leap compared to UHS-I is enormous.

Capabilities and availability in the market

The supply is still limited, although the outlook promises to change quickly. Lexar has microSD Express in 256GB, 512GB and 1TBwith the latter priced around $199. This trio covers the sizes that are most relevant to a modern console, where games take up tens of gigabytes.

SanDisk, for its part, lists a microSD Express model on its website with maximum capacity of 256 GBThe reasonable expectation is that, coinciding with the launch of the Switch 2, more 512GB and 1TB variants from other manufacturers will arrive. Samsung has been mentioned as a likely player, given its expertise in NAND flash memory and controllers.

Prices: How much does it cost to upgrade to Express?

The impact on your wallet is real. A quality 256GB UHS-I microSD card can be bought for around $20 at many reputable retailers. In Spain, it's common to see a SanDisk Extreme 256 GB for 25-30 euroswith very decent sustained speeds for photo, video and mobile devices.

At Express, the price goes up. A 256GB microSD Express card costs around $60For the same capacity, we're talking about nearly three times the price of UHS-I. And if we compare it to the SSD world, for that amount you can find 1TB internal drives from well-known brands, with four times the storage space.

Prices should come down with There. The success of Switch 2 will boost productionAnd with it will come more competition and a better balance of supply. But at launch, the perception of higher prices is inevitable, adding to other increases: the console costs between $100 and $150 more than the previous model, controllers go up by about $10, and a replacement charging dock can cost $50, not to mention new games that are $10-$20 more expensive.

Quick comparison between a popular UHS-I card and a microSD Express card

To put the numbers down, nothing beats a table with key parameters of two 256 GB cards, a well-known UHS-I and an Express. The differences in reading, latency, interface, and price They allow you to see at a glance why Express is a game-changer on demanding consoles and cameras.

Feature	UHS‑I 256 GB type SanDisk Extreme	microSD Express 256 GB
Reading speed	Up to 190 MB/s	Up to 985 MB/s
Interface	UHS-I	PCIe + NVMe in SD Express mode
Latency	Media	Very low
Compatibility	Virtually universal	Only on hosts with SD Express support
Half price	25‑30 euros	Around 60 euros

Even with that forcefulness, there are nuances. Sustained writing rules in actual useAnd here Express wins again: the official ranges of its E/EX label go from 150 to 600 MB/s minimum, compared to the 10-30 MB/s base of U1/U3, and the 650 MB/s write speed figures advertised by some Express models reinforce that leap.

How do these speeds affect gaming?

Modern games constantly stream textures and world data, and that penalizes any storage bottleneck. A slow card results in popping, lag, and jerking. when the engine doesn't receive what it needs on time. At one extreme, PS5 It solves this with a super-fast internal SSD and requires 5.500 MB/s for compatible expansions.

Switch 2 doesn't raise the bar that much, but by integrating faster internal UFS and requiring microSD Express for expansion, It reduces loading times and buffers the streaming load.If you install a game on Express, the menus will usually load faster, fast travel will be quicker, and scenes will play smoothly without buffering due to lack of bandwidth.

Purchasing tips and best practices

If you have to buy, prioritize well-known brands like Samsung, SanDisk, or Lexar. Be wary of generic brands and impossible bargains in marketplaces, because counterfeit stock is rampant and a real headache. It's better to pay a little more for reliability and a guarantee that you won't risk your games and photos.

Think about your actual usage. For Switch 2, 256-512 GB will be the sweet spot in the short term1 TB is available as a premium option when prices drop. Check that your host supports SD Express, update the firmware if necessary, and avoid filling the card completely, as performance and lifespan benefit from having some free space.