Well m.2 sata would be using one lane as sata with an ahci controller elsewhere (probably embedded in a chipset or cpu).
PCIe AHCI have the controller on the m.2 device, maybe better than sata speeds? But I think to boot from an unexpected AHCI controller you might need a boot rom? And why would you put a boot rom on a device that's all about storage?
PCIe AHCI have the controller on the m.2 device, maybe better than sata speeds? But I think to boot from an unexpected AHCI controller you might need a boot rom? And why would you put a boot rom on a device that's all about storage?