The first computers I used in my life had nothing but floppy drives. One for the operating system and one for the software you wanted to run. Even as hard drives and CD-ROM drives appeared on the scene, the humble floppy stuck around for most of that time until USB flash drives finally filled that need.
However, USB drives still aren't an exact substitute for the way we used floppy disks. After all, you're essentially carrying the whole drive with you, rather than just the storage media. I've been using SD cards as mobile storage for years, but they are just too slow for general modern computer use—but what about SD Express?
MicroSD Express turns a memory card into a tiny PCIe drive
While MicroSD Express cards might look like normal SD cards on the outside, on the inside things couldn't be more different. These cards combine the form factor of SD cards with the NVMe protocol used by modern SSDs, and the PCIe bus. The result is what's effectively a mini-SSD that can read data at up to 985MB/s and write it at up to 700MB/s.
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Additionally, these cards have many of the other advantages of true SSDs when it comes to parallel operations and random read requests. Which makes them suitable to run software from. This is why the new Nintendo Switch 2 can run video games like Cyberpunk 2077 from MicroSD Express cards.
While this is much slower than the typical M.2 NVMe drive people use in their computers, MicroSD Express cards can be significantly faster than SATA SSDs, which are still in wide use and are still more than fast enough to run most software without issue. That includes modern games with intense data streaming too.
PCs lost their universal removable storage
Corbin Davenport / How-To Geek
While it's normal for laptops to have standard SD card readers in them, it's not at all usual for laptops, and especially desktops, to have MicroSD Express card readers. Which is a pity, because PCs don't have a solution like the floppy disk in modern times, and I think MicroSD Express could fit that bill just fine.
You might say that USB has solved this and we don't need it, but when I need to use USB storage, I'm always hunting either for an open port or for a port that matches the performance of the drive I'm trying to connect. There's something to be said for a dedicated external storage slot on a computer.
Besides, since the actual drive stays in the computer, the cards take up way less physical space than even the very smallest USB drive. It's also not insignificant to have a disk that goes completely into a drive, and doesn't dangle or stick out of the side the way a USB external storage device does.
Internal SSDs are expensive, and even with 2TB of storage, I am always running out. Moving those SSDs to USB doesn't do anything about the cost, and it's bulky and inconvenient. Yet, I use external storage a lot for actively running software, which means I have to use those SSDs. There's no real alternative.
Having a small removable card that's fast enough for just about any normal computer application, is much smaller, cheaper per gigabyte, and can be swapped out in seconds seems like a niche that needs filling.
Why SD Express hasn't taken off yet
Lexar
MicroSD Express has been around for quite a while now, but it hasn't made much of an impact. The MicroSD Express USB readers you can buy today are a little pricey. Though they are at least backwards compatible with regular MicrosSD cards. Even high-end laptops like MacBooks don't come with this newer card reader as standard.
So it's not that strange that this format hasn't taken off yet. It's only now with the release of the Nintendo Switch 2, which uses MicroSD Express for storage expansion, that there's public interest. I expect that Nintendo will sell millions and millions of these consoles, hopefully helping to drive the price of the cards down. Now that it's of interest to more than just photo and video nerds.
I hope that once people realize that MicroSD Express cards can effectively replace USB SATA SSDs and even USB NVMe drives (which don't perform much better) that there will be more demand for them. Of course, while MicroSD Express cards are much more robust than old SD cards, they aren't as robust as traditional SSDs. So those drives still have a niche best served by hardier NAND flash types.
What would make SD Express matter?
I don't think SD Express cards will catch on for computer users until we start seeing more laptops with MicroSD Express readers built in. An additional $100 fee for a format you might not think you have a need for is a tall order. However, once someone has a drive capable of reading these cards included in the price of a new computer, then it makes sense to buy the media for the hardware you already have.
SSDs are awesome, but they aren't great as removable media, and SD cards and flash drives are too slow and unreliable in comparison. So I really think there's a nice niche between those two solutions where SD Express will fit in perfectly.
