The controllers provide independent PHYs. Each PHY supports SAS link rates of 3 Gb/s, 6 Gb/s, and 12 Gb/s, and SATA link rates of 3 Gb/s and 6 Gb/s. Each of the controller PHYs connect to one controller port.
Direct connect (port-to-port) disk drives can take advantage of the stated data transfer capability. Connecting one controller port to an expander backplane provides the maximum data transfer capability per backplane connection.
Intel® 12 Gb RAID controllers connected to a 12 Gb expander, which is then connected to 6 Gb drives, will show a 12 Gb port connection speed in the RAID configuration utilities, Intel® RAID Web Console 2, and the RAID BIOS configuration utility. This is because from the controller’s point of view, it has a 12 Gb connection to the expander. From the expander point of view, it has a 12 Gb connection to the controller but a 6 Gb connection to the drives, and the expander is consolidating the 6 Gb dataflow in and out of the drives into a 12 Gb stream in and out of the controller. So from the controller point of view, it only aware of a 12 Gb connection.