All memory cards are developed with roadmaps that plot out future capacities and transfer speeds. Until quite recently, the roadmap for the SD card saw capacities topping off at 2TB. Big, yes, but nothing compared to a refreshed SD standard (SD 7.0) which will see capacities soar to a potential 128TB in both traditional and Micro sizes with transfer speeds reaching a blistering 985MB/s.
By way of comparison, current UHS-II cards have a maximum transfer speed of 312MB/s and the forthcoming UHS-III cards will reach 624MB/s.
Key to the new SD7.0 specification is the use of PCIe and NVMe interfaces, which will essentially enable SD cards to become removable solid state drives.
SD cards conforming to the new standard will be backwards compatible with existing SD card devices–though those older devices won’t be able to tap into the higher speeds.
The new standard supports two variants of new SD cards–SD Express, for the highest speeds, and SD Ultra Capacity (SDUC) for the highest capacities.
You can get the full background in the SD Card Association’s white paper. As for when we’ll see products incorporating the new standard, the SDA didn’t specify but we’ve reached out to them for more details.