NUC M.2 vs U.2 vs 2.5"

Easily proofed wrong. But surely not something you can just plug in to a NUC."+NVMe+drive

The benefits of NVMe are lost when they have to be passed across on the SATA protocol. So you are paying extra for performance you cannot exploit fully I would have thought…
When using M.2 NVMe you are connecting directly to the CPU bus. You can’t do that via a SATA cable into the SATA bus. Or have I missed something? Perhaps these have to be on a PCIe bus so have to be plugged into a special card?

I should have clarified… 2.5" come in multiple forms, the common one and this not so common thing you found, which is called U.2, and is basically a cabled version of M.2.

Please ignore all U.2 or something called SFF-8639 – it’s just wrong for everyone here.

@Henry_McLeod – see above about U.2.

I moved this stuff out of the other topic as to not confuse newcomers.


This is correct. Adapters exist for PCIe but also M.2 NVMe slots. Or you can use a (server-)mainboard with these connectors already onboard.

  • If you have a spare PCIe connector you might be better off with a NVMe SSD that’s directly mounted on the adapter board unless you feel the need to mount more than one of these drives and a single adapter card can provide the multiple connectors you need.
  • If you have a spare M.2 NVMe connector you’re better off using a M.2 NVMe SSD directly.

But not relevant to anything with the space constraints of a NUC?

These are not meant for NUCs!

You can do this if you really want and have the money for experiments like these, but it’s not beneficiary in any way for the use purposes a NUC is designed for. Just stick with a common M.2 SSD.