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.
Now that you understand all the important details that separate SSDs and SSD types, your choices should be clear. Remember that high-end drives, while technically faster, won’t often feel speedier than less-spendy options in common tasks.
So unless you’re chasing extreme speed for professional or enthusiast reasons, it’s often best to choose an affordable mainstream drive that has the capacity you need at a price you can afford. Stepping up to any modern SSD over an old-school spinning hard drive is a huge difference that you’ll instantly notice. But as with most PC hardware, there are diminishing returns for mainstream users as you climb up the product stack.
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.