Why is transfer speed slow on D2-310/D4-310/D4-300/D5-300?

Please check the following:
1.How’s the transfer speed of hard drives? SATA I (1.5Gbps), SATA II (3Gbps), SATA III (6Gbps)?
2.What is the partition format of the hard drives installed on the TerraMaster device? NTFS is fastest; FAT32 the 2nd, while exFAT is the slowest.
3.What is the partition format of the hard drives in the computer? NTFS is fastest; FAT32 the 2nd, while exFAT is the slowest.
4.What is the interface type of the USB port which connects the TerraMaster device and the computer? Is it USB2.0, USB3.0 or USB3.1?
5.The transfer speed also has something to do with the RAID mode. RAID 0 or RAID 10 is fast, while RAID 1, RAID 5, SINGLE Disk and CLONE are slower.