Using the JMB585 chipset, the SI-PEX40139 can provide extra 5 Port SATA III to any free PCI-e x4 slot with PCIe Gen3 x2 bandwidth. For the storage solution based on data transfer of multiple hard drives, the newly added FIS-based switching design can overcome the bottlenecks created by operating multiple SATA storage devices simultaneously. The data transmission rate of the JMB585 can achieve to 1700MB/s, which is the maximum transfer speed of PCIe Gen3 x2.