Z270 formula 9 upgrading to z790 formula. I have five hard drives, four concatenated and the fifth one holds the windows os on my z270. It has six sata slots.. five being used for hard drives. My z790 only has four sata slots so l'm considering putting a 4 TB m2 2280 4tb ssd into the M2 3 slot and 4 hard drives on the sata slots. Why would I want to put one into the M2 1 slot? Why would I use the m2 1 2280 slot over the m2 3? Especially since you share the bandwidth and lose your pci slot?