The SD Association unveils microSD Express format for mobile with data transfer speeds of up to 985 MB/s, lower power consumption, and backwards compatibility
Context & Ripple Effects
The SD Association's microSD Express launch lands mid-race between removable and embedded mobile storage: days earlier, Samsung began mass-producing 512GB eUFS 3.0 chips running at 2,100 MB/s — more than twice the new card format's 985 MB/s ceiling. The format's backwards compatibility is the defensive move, keeping billions of existing microSD cards usable while the interface catches up.
Capacity was already solved — SanDisk had just shown a $450 1TB microSD — so this announcement is about bandwidth and power, the two specs that determine whether phone makers bother keeping a card slot at all.
First-order effects
- Phone makers weighing a microSD slot get a removable option whose 985 MB/s no longer bottlenecks app loading or 4K capture, though it still trails Samsung's embedded eUFS 3.0 on raw speed.
- Card vendors gain a premium tier to build toward, since Express cards require new controllers even as they read legacy media.
Second-order effects
- Samsung's embedded-flash advantage pressures flagship designs to drop slots entirely unless card makers close the speed gap quickly — making slot retention a cost-and-spec decision rather than a default.
- Express-capable readers and host controllers become a new component category, letting accessory makers differentiate on bus support rather than just capacity.
Third-order effects
- The Association kept iterating — its later SD 8.0 spec pushed SD Express to 3,940 MB/s via PCIe 4.0 — signaling that removable storage now tracks the PCIe roadmap instead of a proprietary one, keeping cards competitive with embedded flash on speed if not integration.
- If the pattern holds, the card slot survives as an expansion path for high-capacity devices while embedded UFS owns performance-critical storage, splitting the market by role rather than replacing either side.
The trend: Removable storage standards are re-platforming onto PCIe so memory cards can keep pace with embedded UFS flash and justify their place in phones.