SATA Express and PCIe based SSD's are separate protocols, cabling and connectors. The title is wrong and needs to be corrected along with the technical details of this post.
SATA Express is based on the SATA protocol and uses a MB connector that can be used as multiple SATA ports/drives or used with a single SATA express drive. SATA Express shouldn't even be mentioned here because the drive mentioned in this article is a NVME based 2.5" SSD.
SATA express is a complete waste of MB space and has never lived up to its promises. Can you even buy a SATA express drive at all?
I feel like I really need to address this mess of a post.
1.) SATA-Express and PCIe are not separate protocols. They both use the NVMe protocol. And connection standard wise, SATA-Express is exactly the same as a PCI-E x2 link, but in a different form factor.
2.) SATA-Express is
NOT based on the SATA protocol and doesn't just use multiple SATA ports for a single SATA-Express drive. SATA uses the ACHI protocol(primarily). SATA-Express uses the much improved NVMe.
3.) SATA-Express is only called that because it incorporates two SATA connector plugs(even though they aren't used as SATA ports when in SATA-Express mode, they are used to transmit PCI-E data), and because the term SATA was associated in the consumer space with storage drives and they wanted people to easily know SATA-Express was a storage connector. This was done specifically to not waste board space, so that people without SATA-Express drives wouldn't have a completely unused port just sitting there. They could still use it with standard SATA drives if they wanted.
As for the Super Talent SSD, obviously it uses the 32 Gb/s U.2 standard. When SFF-8639 is used for SATA Express, it's only 10 Gb/s, wired thru the chipset, not the PCIe lanes.
It is still using PCI-E lanes. The speeds achievable depend on how they are wired. SATA-Express is theoretically capable of 16Gb/s, as it provided up to 2 PCI-E 3.0 lanes. U.2 provides up to 4 PCI-E 3.0 lanes, so 32Gb/s.
However, the U.2 standard doesn't actually specify that the lanes must be PCI-E 3.0. So it is possible to have a U.2 slot that only provides 16Gb/s using PCI-E 2.0 lanes. And in fact, if you use one of those M.2 to U.2 adapters on most M.2 slots, you are only going to get a PCI-E 2.0 x2 link, so your at the 10Gb/s anyway. But really, that raw bandwidth is not where the speed of these drives comes from anyway. So you are unlikely to notice the difference between a 10Gb/s SATA-Express and a 32Gb/s U.2 drive. The HVMe standard is what really makes these drives feel so fast, it drastically improves the random read numbers.
