Should I connect the hdd in sata 3 or 4 or the ssd in the 3 or 4?

How to upgrade Mac Pro 5,1 disk slots to SATA 3 sata 3 slot 2 Slot on Motherboard; Two types of SSD ; What are the performance differences between SSDs? How to sata 3 slot If a PCIe gen 3 slot has been downgraded to PCIe gen 1 or 2 via BIOS your new card won't provide you with the bandwidth you need Also, I

sata m2 slot Socket 3: SSD Drive Socket with SATA or up to four PCIe lanes Important Notes: Please refer to your motherboard documentation to make sure that