Samsung launched a new MicroSD card at the end of February, and while that’s unremarkable in and of itself – the Korean brand is one of the largest SD card manufacturers – the new card is something completely different. They use the SD Express standard and have sequential read speeds of up to 800MB/s, which is faster than SATA SSDs.
hardwired
In Hardwired, AC Senior Editor Harish Jonnalagadda takes an in-depth look at all things hardware, including phones, storage servers, and routers.
Crucially, the standard is nearly eight times faster than UHS-I cards at 104MB/s and UHS-II at 312MB/s. SD Express MicroSD cards start at 256GB and go up to 1TB in capacity, and they use Samsung’s V-NAND technology, which is similar to what the brand uses in its regular SSDs.
There’s clearly a lot to like about these cards, even if you don’t buy Samsung’s claims about promoting on-device artificial intelligence. But the biggest problem with the SD Express standard is that, despite being around for the better part of a decade, it hasn’t made any mainstream progress, and that’s unlikely to change.
What’s more, MicroSD cards don’t work on the best Android phones; of course, Samsung still makes a few mid-range Galaxy A phones with MicroSDXC slots, but that list gets older with each generation. Come shorter and shorter. All phone manufacturers have abandoned the standard on their flagships, and for good reason – while SD Express is a huge improvement over UHS-I, it’s still no match for UFS 4.0 storage.
All flagships released in 2024 will feature UFS 4.0 storage, a standard with sequential read speeds of up to 4,000MB/s, five times faster than SD Express. Micron just launched its new UFS 4.0 module, which is small but delivers sequential read speeds of 4,400MB/s, and UFS 5.0 is coming soon.
Phone manufacturers have been using eMMC storage for years, and since the standard isn’t much faster than the popular MicroSD card, they have no problem offering expandable storage on their devices. But when UFS storage started to gain momentum nearly a decade ago, they ran into a dilemma: The standard offered performance similar to NVMe SSDs and far more than MicroSD.
Brands could continue to offer MicroSD slots on their devices, but that would mean a significant difference in performance between onboard storage and expandable modules, or avoid the port entirely – which is where we end up. That won’t change with the introduction of faster MicroSD cards. Brands can make more money by promoting users to buy phones with higher storage capacity.
I like the idea of expandable storage; I use all the M.2 slots on my console, I plugged in a 2TB SSD in the PlayStation 5 to increase the limited storage available on the console, and plugged in a 2TB M. .2 2230 SSD I got the handheld. But I’ve never felt the need to do this on my phone – although it would make transferring data to a new device much easier.
That’s the second reason why most phones don’t have MicroSD card slots: reliability. I’ve had several instances in the past where MicroSD cards failed and I ended up losing the data stored on those cards. So when I got an LG G4 ten years ago, I decided not to use a MicroSD card and started backing up the data on the phone to external sources—Google Photos on the cloud and a NAS on my home network.
Unless better standards emerge, phone manufacturers are unlikely to consider offering expandable storage on their devices. Even so, I doubt most brands would care; ports are at a premium these days, and iPhones don’t even have a SIM card tray (thankfully only in North America). Considering the current state of UFS storage and the direction of the industry, scalable storage is not making a comeback.