OptiPlex 3070 SFF + Intel 13th Gen – What is the actual PCIe generation of the M.2 NVMe slot?

Message: Hi, I'm using a Dell OptiPlex 3070 Small Form Factor with an Intel Core 13th Gen processor and a Samsung 990 EVO NVMe SSD. According to Samsung Magician, I'm getting sequential speeds of ~3479 MB/s read and ~3607 MB/s write, which clearly suggests the M.2 slot is operating at PCIe Gen3 x4 or possibly even Gen4 x4.

However, the official Dell documentation (PDF) states that the M.2 NVMe slot is limited to PCIe 2.0 x4, which contradicts the actual performance I'm seeing.

Could someone from Dell please clarify:

• What PCIe generation does the M.2 NVMe slot truly support on the OptiPlex 3070 SFF when paired with a 13th Gen Intel CPU?

• Are there differences based on CPU model or motherboard revision?

• Is the documentation outdated for newer configurations?

Thanks in advance!