I have a Z270 Extreme 4 P2.20 motherboard. When I go to the UEFI, it tels me there are 2 M2 drives. M2-1 is a Samsung 250Gb M2 M2-2 is a Corsair MP600 1Tb M2 I have 4 hard disks, 500Gb SSD 2x 1Tb and 1 1Tb standard Sata. These are plugged into a1, a2, 2, 3 This leaves 0,1, 4, 5 as the M2 slots as shown in the M2 sata switch option.. All of these show up in the UEFI When I got to Windows 7, there is no sign of the Corsair M2 drive in M2-2. Can someone give me any idea of why this should be?