Old ICH7 SATA-2 question

[Michael BlackHeart]

Hello there, I've got a question about SATA.

I've got ASUS P5GC-MX/1333 with ICH7. (SATA2 support)
A few HDD with SATA2.

system:
uname -a
FreeBSD diablo.miekoff.local 9.1-STABLE FreeBSD 9.1-STABLE #1 r246666:
Tue Feb 12 00:19:07 MSK 2013
root at diablo.miekoff.local:/usr/obj/usr/src/sys/DIABLO64  amd64


camcontrol info

camcontrol iden ada2
pass2: <ST3500320AS SD1A> ATA-8 SATA 2.x device
pass2: 150.000MB/s transfers (SATA, UDMA5, PIO 8192bytes)

protocol              ATA/ATAPI-8 SATA 2.x
device model          ST3500320AS
firmware revision     SD1A
serial number         5QM3LB0N
WWN                   5000c50011db1e03
cylinders             16383
heads                 16
sectors/track         63
sector size           logical 512, physical 512, offset 0
LBA supported         268435455 sectors
LBA48 supported       976773168 sectors
PIO supported         PIO4
DMA supported         WDMA2 UDMA6
media RPM             7200

Feature                      Support  Enabled   Value           Vendor
read ahead                     yes      yes
write cache                    yes      yes
flush cache                    yes      yes
overlap                        no
Tagged Command Queuing (TCQ)   no       no
Native Command Queuing (NCQ)   yes              32 tags
SMART                          yes      yes
microcode download             yes      yes
security                       yes      no
power management               yes      yes
advanced power management      no       no
automatic acoustic management  no       no
media status notification      no       no
power-up in Standby            no       no
write-read-verify              yes      yes     2/0x2
unload                         no       no
free-fall                      no       no
data set management (TRIM)     no

smartmontools info

smartctl -a /dev/ada2 | more
smartctl 6.0 2012-10-10 r3643 [FreeBSD 9.1-STABLE amd64] (local build)
Copyright (C) 2002-12, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family:     Seagate Barracuda 7200.11
Device Model:     ST3500320AS
Serial Number:    5QM3LB0N
LU WWN Device Id: 5 000c50 011db1e03
Firmware Version: SD1A
User Capacity:    500 107 862 016 bytes [500 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    7200 rpm
Device is:        In smartctl database [for details use: -P show]
ATA Version is:   ATA8-ACS T13/1699-D revision 4
SATA Version is:  SATA 2.6, 3.0 Gb/s
Local Time is:    Sun Feb 24 00:29:47 2013 MSK
SMART support is: Available - device has SMART capability.
SMART support is: Enabled


At this point all seems SATA2 capatible.

But at loading:
atapci0: <Intel ICH7 UDMA100 controller> port
0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0xffa0-0xffaf at device 31.1 on
pci0
ata0: <ATA channel> at channel 0 on atapci0
atapci1: <Intel ICH7 SATA300 controller> port
0xb800-0xb807,0xb400-0xb403,0xb000-0xb007,0xa800-0xa803,0xa400-0xa40f
irq 23 at device 31.2 on pci0
ata2: <ATA channel> at channel 0 on atapci1
ata3: <ATA channel> at channel 1 on atapci1

Looks like it's also SATA2 (SATA300)

But HDD says this:

ada2 at ata2 bus 0 scbus1 target 0 lun 0
ada2: <ST3500320AS SD1A> ATA-8 SATA 2.x device
ada2: 150.000MB/s transfers (SATA, UDMA5, PIO 8192bytes)
ada2: 476940MB (976773168 512 byte sectors: 16H 63S/T 16383C)
ada2: Previously was known as ad2

At this point I've a quiestion - what's the real operation speed and why's that.
And for the record - I can't switch ICH 7 to ahci due to bios limitations.

And one more, I've got netbook with ICH7 (NM-10 mb).
It uses achi driver, and HDD says it's

ahci0: <Intel ICH7 ACHI SATA controller> <...>
ahic0: AHCI v1.10 with 4 3Gbs ports <...>
<...>
ada0: <vendor blah-blah-blah> ATA-8 SATA 2.x device
ada0: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
ada0: Command Queueing enabled

As far as I remember without AHCI there's no NCQ support. But why with
SATA300 controller on P5GC-MX/1333 I've got only 150 transfers? Is
it's a limitations of this driver for old chip?