Asus Z9NA-D6 - Manual (Page 48)

2-28 Chapter 2: Hardware information
4. Hard disk activity LED connector (4-pin HDLED1)
This LED connector is for the storage add-on card cable connected to
the SATA or SAS add-on card. The read or write activities of any device
connected to the SATA or SAS add-on card causes the front panel LED to
light up.
3. SAS connectors (7-pin PSAS1–8 [Blue])
Supported by the ASUS ® PIKE Card, these connectors are for the SAS signal
cables for SAS hard disk drives that allows up to 6Gb/s of data transfer rate.
If you installed SAS hard disk drives, you can create a RAID 0, RAID 1, RAID
10, or RAID 5 configuration.
The actual data transfer rate depends on the speed of SAS hard disks installed.