Today at Flash Memory Summit, Toshiba is debuting a new form factor for NVMe SSDs that is small enough to be a removable alternative to soldered-down BGA SSDs. The new XFMEXPRESS form factor allows for two or four PCIe lanes while taking up much less space than even the smallest M.2 22x30mm card size. The XFMEXPRESS card size is 18x14x1.4mm, slightly larger and thicker than a microSD card. It mounts into a latching socket that increases the footprint up to 22.2x17.75x2.2mm. For comparison, the standard sizes for BGA SSDs are 11.5x13mm with a PCIe x2 interface or 16x20mm with a PCIe x4 interface.

XFMEXPRESS is intended to bring the benefits of replaceable storage to devices that would normally be stuck with soldered BGA SSDs or eMMC and UFS modules. For consumer devices this opens the way for aftermarket capacity upgrades, and for embedded devices that need to be serviceable this can permit smaller overall dimensions. Device manufacturers also get a bit of supply chain flexibility since storage capacity can be adjusted later in the assembly process. XFMEXPRESS is not intended to be used as an externally-accessible slot like SD cards; swapping out an XFMEXPRESS SSD will require opening up the case of the device it's installed in, though unlike M.2 SSDs the XFMEXPRESS socket and retention mechanism itself is tool-less.

XFMEXPRESS will allow for similar performance to BGA SSDs. The PCIe x4 host interface will generally not be the bottleneck, especially in the near future when BGA SSDs start adopting PCIe gen4, which the XFMEXPRESS connector can support. Instead, SSDs in these small form factors are often thermally limited, and the XFMEXPRESS connector was designed to allow for easy heat dissipation with a metal lid that can serve as a heatspreader. Toshiba partnered with Japan Aviation Electronics Industry Ltd. (JAE) to develop and manufacture the XFMEXPRESS connector.

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  • Dwedit - Tuesday, August 6, 2019 - link

    You ever seen those tiny, flat ribbon cables that are attached to a board by a locking clip? I've broken several of those locking clips in my time. This looks just like one of those.

    I'm concerned about how easy this would be to accidentally break. M2 doesn't have that problem.
  • hubick - Tuesday, August 6, 2019 - link

    What about CFExpress? How does this compare? Why not one or the other?
  • LordConrad - Wednesday, August 7, 2019 - link

    Other than removabilty, how does this compare to SDexpress?
  • valinor89 - Wednesday, August 7, 2019 - link

    This looks, phisically, like the way we put sim cards under the battery of mobile phones of yore. Not exactly an innovative connector design...
  • Siliconathlete - Thursday, August 8, 2019 - link

    Not to be against this but too many interfaces will ruin this space..
  • Diogene7 - Friday, October 18, 2019 - link

    I think I would be more interested that it tzkes the form of some kind of (nano) SIM card tray, that is externally user accessible : it would allow user to easily access and upgrade the main device storage.

    As it is compatible with PCI-express 4, and maybe PCI-e 5 later on, it would even maybe replace micro-SD cards in the future due to much better data write & data read spead...
  • Wereweeb - Saturday, February 6, 2021 - link

    Mr. Tallis, I'm not sure if you are aware, but this website appears to have wholesale copied your post and reposted as if it were theirs:

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