FAQ - Frequently Asked Questions - Knowledge Base
[Thunder2 Duo Pro] Why don't I get better transfer rates?
The best performance can be achieved via Thunderbolt connection and with two SSD's in RAID 0. The actual transfer rate with this kind of setup is around 600-800MB/s.
The USB interface will max out at around 400MB/s, so for better speeds, the Thunderbolt connection is a must. The maximum performance of the Thunderbolt 2 connection (after overhead) is around 1375MB/s but the SATA controller that bridges the PCI Express Gen2 x2 interface to two Serial ATA 6Gps ports has a maximum transfer rate (after overhead) of about 800MB/s. Because of that, the upper limit for two drives in RAID 0 is around 700-800MB/s. For a single drive, it can run at full SATA 6Gbps (SATA-III) speeds of around 500MB/s.
For regular spinning hard disk drives, the limit is the drive itself. At best, a single drive can go around 200MB/s and two drives in RAID 0 up to around 400MB/s.