FreeBSD 9.2 shows SATA3 drives as SATA2

Question

I'm running FreeBSD 9.2 on an Intel S2600GZ server board with 4 Intel SSDs. Both the server board as well as the disks are SATA3 capable. However, FreeBSD seems to think they are SATA2. Nowhere in system configuration are the disks limited to SATA2.

This is an excerpt from dmesg:

ahci0: <Intel Patsburg AHCI SATA controller> port 0x3070-0x3077,0x3060-0x3063,0x3050-0x3057,0x3040-0x3043,0x3020-0x303f mem 0xd0d00000-0xd0d007ff irq 21 at device 31.2 on pci0
ahci0: AHCI v1.30 with 6 6Gbps ports, Port Multiplier not supported
ahcich0: <AHCI channel> at channel 0 on ahci0
ahcich1: <AHCI channel> at channel 1 on ahci0
ahcich2: <AHCI channel> at channel 2 on ahci0
ahcich3: <AHCI channel> at channel 3 on ahci0
ahcich4: <AHCI channel> at channel 4 on ahci0
ahcich5: <AHCI channel> at channel 5 on ahci0
# ...
da0 at isci0 bus 0 scbus0 target 0 lun 0
da0: <ATA INTEL SSDSC2BA20 0265> Fixed Direct Access SCSI-5 device 
da0: 300.000MB/s transfers
da0: Command Queueing enabled
da0: 190782MB (390721968 512 byte sectors: 255H 63S/T 24321C)
# ... and so on for the other disks

The relevant settings for disks in BIOS are (the first two are greyed out and not changeable):

AHCI Controller Configuration: 2 ports of 6Gb/s SATA
SATA/SAS Controller Configuration: 8 ports in SATA mode

AHCI Capable SATA Controller: AHCI
AHCI HDD Staggered Spin-UP: Disabled
SAS/SATA Capable Controller: Intel RSTe

I'm running ZFS, by the way, if it's got anything to do with it.

What can I do to make the system understand these are SATA3 disks and use them at full speed?

Answer 1

After perusing the technical specification, it turns out that Intel S2600GZ has only the two AHCI SATA ports that work in SATA3 mode and the remaining 8 are only SATA2, unfortunately. So to answer the question, the server board is in fact not capable of running all the disks in SATA3 and it is not a problem with FreeBSD.