Most of the mini-ITX boards I found have up to 6 SATA3 ports and a m.2, but if the m.2 is used, then (usually) only 4 SATA ports are left, since some of SATAs share the pci-e lane with the m.2.
Are there any boards that can be used with both m.2 AND more than 4 SATA drives?
Are there any boards that can be used with both m.2 AND more than 4 SATA drives?