New SDUC Memory Cards Could Hold Up to 128TB of Data in the Future

Representatives of the SD Association have announced that they’re introducing a new memory card specification that promises to shatter existing storage limitations. SD cards manufactured according to the current rules can only ever hold up to 2TB of data. This limitation has been in place for about nine years, and it still hasn’t been reached.

Some readers may remember that SanDisk created prototype 1TB SD cards in 2016. While these are hypothetically the largest ever made, they never went into production and therefore they’re not currently available for purchase. SanDisk’s public relations crews back then said that the large SD cards would be necessary to hold large 4K and VR videos.

File sizes continue to grow as a result of advances in multimedia resolution. However, it’s become difficult to create SD cards that are as large as those as SanDisk wanted to make. Even 512GB SD cards cost several hundred dollars, which price them out of most people’s devices.

SD Express, the new standard, hopes to do away with some of these issues by using advanced PCI Express and NVMe technology. Cards making use of extensions to the PCIe interface could theoretically boast transfer rates greater than 980 MB/s and hold a great deal more data.

While SDXC cards are still tethered to the old 2TB limitation, new SD Ultra Capacity (SDUC) cards would hypothetically hold up to 128TB. This places them in a category that’s outside even many consumer-grade electromechanical hard disks.

It’s currently unclear how long it would take hardware manufacturers to ever reach this new limit, but the SD Association did release a white paper detailing how the new standard will work.

Commentators have been concerned about bus speeds on larger cards for some time, but the new standard apparently fixes the problem to some degree by reorienting the way that SDUC cards communicate with the host device.

Current SDXC cards larger than 32GB are required to come with preformatted with the exFAT file system. While exFAT can theoretically massive storage volumes, the MBR partition scheme many of these cards ship with can’t. More devices in the future may have to use a different standard as a result.

John Rendace
John is a GNU/Linux expert with a hobbyist's background in C/C++, Web development, storage and file system technologies. In his free time, he maintains custom and vintage PC hardware. He's been compiling his own software from source since the DOS days and still prefers using the command line all these years later.