[alexdbird]

I am 100% sure. It is indeed an SM951/M2/ACHI[sic, that's what's printed on it], I have it in front of me. It went in the only system I've built in the last 15 years, so there's no room for confusion.

It had to be AHCI because macOS didn't support NVMe in this era, and the motherboard was also chosen for Hackintosh compatibility, but I only ever used it as a data drive because of the boot issues. That was probably the best option for its use as a fast compile machine anyway, but it did become a PITA when I wanted to sell the machine.

I'm afraid I am not familiar with this technology - as I said I am not an expert - so perhaps driver is the wrong word. Perhaps I did end up reading advice relating to the NVMe variant, information was very hard to come by. All a very small historical footnote now anyway!