terry4536 :
What does M2A indicate? Does M2P indicate M and P key?
I think that's just an internal naming convention.
From the user manual, pg 34:
http://download.gigabyte.us/FileList/Manual/mb_manual_z390-audio.pdf
Installation Notices for the PCIEX4, M.2 and SATA Connectors:
Due to the limited number of lanes provided by the Chipset, the availability of the SATA connectors may be affected
by the type of device installed in the M2. sockets. The M2M connector shares bandwidth with the SATA3 4, 5
connectors. The M2A connector shares bandwidth with the SATA3 1; the M2P connector shares bandwidth with
the PCIEX4 connector. Refer to the following tables for detail