Where is the port 7 information coming from?
The specifications do not make any mention of sata port sharing, except for the eSATA/USB Combo Connector.
The following information is from the specifications in your motherboard user manual:
Storage Interface South Bridge:
6 x SATA 3Gb/s connectors (SATA2_0~SATA2_5) supporting up to 6 SATA 3Gb/s devices
Support for SATA RAID 0, RAID 1, RAID 5, and RAID 10
Marvell 9128 chip:
2 x SATA 6Gb/s connectors (GSATA3_6, GSATA3_7) supporting up to 2 SATA 6Gb/s devices
Support for SATA RAID 0, and RAID 1
GIGABYTE SATA2 chip:
1 x IDE connector supporting ATA-133/100/66/33 and up to 2 IDE devices
2 x SATA 3Gb/s connectors (GSATA2_8, GSATA2_9) supporting up to 2 SATA 3Gb/s devices
Support for SATA RAID 0, RAID 1, and JBOD
Storage Interface w JMicron JMB362 chip:
2 x eSATA 3Gb/s connectors (eSATA/USB Combo) on the back panel sup- porting up to 2 SATA 3Gb/s devices
Support for SATA RAID 0, RAID 1, and JBOD
iTE IT8720 chip:
1 x floppy disk drive connector supporting up to 1 floppy disk drive
note: eSATA/USB Combo Connector
This connector supports SATA 3Gb/s and USB 2.0/1.1 specification. Use the port to connect an external SATA device or a SATA port multiplier; or use this port for USB devices such as a USB keyboard/mouse, USB printer, USB flash drive and etc.
Page 56 in the user manual has information for bios settings for the Marvell and JMicron controllers.