SD cards have revolutionized the way we store data. The perfect combination of portability and low cost made this unmistakable format a leader, but it still has several weaknesses to overcome. Two of the most important, capacity and speed, will be handled by the new SD Express specification, which promises a maximum of 128 terabytes per card and a transfer rate of 985 megabytes per second, courtesy of NVMe and PCI Express technologies.
The amount of data we generate each day continues to grow. From 360-degree recordings to 4K video, we need ever-greater capacity, and current storage media are already feeling the pressure. Hard drives have reached the 12-terabyte mark, a truly impressive number, but it's only a matter of time before even those magnetic monsters become insufficient. As unlikely as it may seem, all arrows point to flash memory. I imagine our readers remember the announcements by Seagate and Toshiba, but today it's the SD Card Association's turn, which announced SD Express.
SD Express: Capacity and Speed
SD Express is an element within version 7.0 of the SD specification, and brings two critical advantages for the future of the format: capacity and speed. First, SD Express extends the theoretical maximum of SDXC (2 TB) to a chilling 128 terabytes, a little more than 26 million photos at 5 MB per JPG. Now, that's useless if the transfer remains slow as a snail. The solution comes through the PCI Express interface combined with the NVMe protocol. The new specification mentions a limit of 985 megabytes per second, equivalent to PCI Express 3.0 x1. The additional bandwidth will require extra pins on the cards, something we can already see in UHS-II and UHS-III units.
Of course, the question of 128 terabytes is 'how, when, and how much', and the available information reveals nothing about that. SD Express will give rise to new cards, new readers, and new devices with that integrated technology. Conventional SD cards are very popular and won't disappear overnight, but everything will be much better for users if the updated specification speeds up a bit.
