UHSIIIIII

UHSIIIIII is a term that appears in speculative discussions to denote a proposed next generation of Ultra High Speed (UHS) memory card interfaces, intended to succeed UHS-III. It is not an officially ratified standard by the SD Association or any other standards body. The name is used in some roadmaps and online forums to describe a hypothetical specification rather than a published standard.

In these speculative descriptions, UHSIIIIII would aim to deliver substantially higher data transfer rates than UHS-III and would likely require new physical interfaces, signaling methods, or even a shift to alternative transport like PCIe-based signaling on removable cards. Proponents sometimes discuss increased pin counts, improved error correction, and advanced signaling as part of the concept, though exact technical details are not standardized.

As of 2025, no formal technical specification or certification program exists for UHSIIIIII, and no devices or ecosystem partners have publicly announced compliance with such a standard. The absence of an official specification means that interoperability, licensing, and compatibility constraints remain unresolved.

If developed, adoption would depend on industry alignment among memory card manufacturers, device makers, and the SD Association, and would entail new host controllers, firmware, and logistics for licensing and certification. Until a formal specification is released, UHSIIIIII remains a speculative concept rather than a defined standard.

See also Ultra High Speed (UHS), UHS-I, UHS-II, UHS-III, SD Association, SD card.