SATA Interface Version vs. SATA Device Version

[emariz]

This laptop has an Intel HM65 Express chipset (part of the series 6/C200).

I would like to replace the optical disc drive with a second storage drive using a 2.5" SATA to SATA HDD/SDD caddy (disk enclosure). Yet I have a few questions about the SATA versions.

Reading the chipset's data sheet, I found out that:

SATA interface transfer rates are independent of UDMA mode settings. SATA interface transfer rates will operate at the bus’s maximum speed, regardless of the UDMA mode reported by the SATA device or the system BIOS.

The PCH supports SATA 6 Gb/s transfers with all capable SATA devices. SATA 6 Gb/s support is available on PCH Ports 0 and 1 only.
Note: PCH ports 0 and 1 also support SATA 1.5 Gb/s and 3.0 Gb/s device transfers.

Now some information from my system:

Code: Select all

$ dmesg | grep -i ata

[    0.635687] ahci 0000:00:1f.2: AHCI 0001.0300 32 slots 6 ports 6 Gbps 0x11 impl SATA mode
[    0.637355] ata1: SATA max UDMA/133 abar m2048@0xd2607000 port 0xd2607100 irq 25
[    0.637357] ata2: DUMMY
[    0.637359] ata3: DUMMY
[    0.637360] ata4: DUMMY
[    0.637363] ata5: SATA max UDMA/133 abar m2048@0xd2607000 port 0xd2607300 irq 25
[    0.637364] ata6: DUMMY
[    0.948331] ata5: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[    0.948371] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[ 1473.769590] ata1.00: configured for UDMA/133
[ 1473.804488] ata5.00: configured for UDMA/100

Code: Select all

$ dmesg | grep -i scsi

[    2.421102] scsi 0:0:0:0: Direct-Access     ATA      Hitachi HTS54755 A50B PQ: 0 ANSI: 5
[    2.449187] scsi 4:0:0:0: CD-ROM            TSSTcorp CDDVDW TS-L633C  SN01 PQ: 0 ANSI: 5
[    2.512426] sd 0:0:0:0: [sda] Attached SCSI disk
[   10.000160] sr 4:0:0:0: [sr0] scsi3-mmc drive: 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray
[   10.000387] sr 4:0:0:0: Attached scsi CD-ROM sr0

Code: Select all

$ su -c 'smartctl --all /dev/sda'

Model Family:     Hitachi/HGST Travelstar 5K750
Device Model:     Hitachi HTS547550A9E384
User Capacity:    500.107.862.016 bytes [500 GB]
Sector Size:      512 bytes logical/physical
Rotation Rate:    5400 rpm
Form Factor:      2.5 inches
ATA Version is:   ATA8-ACS T13/1699-D revision 6
SATA Version is:  SATA 2.6, 3.0 Gb/s

Thus, I believe that the version of the SATA interface in my laptop is version 3/ 6 Gbps, but those of the currently connected SATA devices are lower (the HDD is version 2.6/ 3 Gbps, and the CD-ROM is version 1/ 1.5 Gbps). It also seems to me that the SATA version displayed by the aforementioned commands is the version of the SATA device and not of the SATA interface. Am I right?

If I add a SSD SATA 3 to my laptop, will it use 6 Gbps? Does it matter in which SATA port it is connected (in the disc drive tray or in the former optical disc tray)?

[tomazzi]

(...) It also seems to me that the SATA version displayed by the aforementioned commands is the version of the SATA device and not of the SATA interface. Am I right?

Yes, this is the device interface version.

If I add a SSD SATA 3 to my laptop, will it use 6 Gbps?

Theoretically Yes - but it can depend on BIOS settings/version/bugs. The only way to confirm this is to connect && check

Does it matter in which SATA port it is connected (in the disc drive tray or in the former optical disc tray)?

Same as above: there may be a difference - depends on what's in the BIOS.

Regards.

[pylkko]

Very likely to support SATA 3 6 Gbps

http://postimg.org/image/81ko026d7/


However, and you might realize this already, many ssd's cannot saturate SATA 2 even. Last time I checked, many manufacturer's ssd's in the lower capacity range would not pull of sequential writes and reads in excess of 3 Gbps, and you needed to have a higher capacity drive (like 512 Gb) in order to reach such speeds. This is because the more cells are available, the more of them can be used simultaneously (I guess). Another things is that, even if you miss some throughput with a lower SATA, how much would that matter to you? Does your computer use consist of daily massive sequential read/writes? Because for most people it probably does not, at all. You would still be able to benefit from quicker access times and the more typical lower size random read speeds that are better on ssd's than on spinning disks.

[emariz]

Another things is that, even if you miss some throughput with a lower SATA, how much would that matter to you? Does your computer use consist of daily massive sequential read/writes? Because for most people it probably does not, at all. You would still be able to benefit from quicker access times and the more typical lower size random read speeds that are better on ssd's than on spinning disks.

You are absolutely right. And I guess even in the worst case scenario (the port of the former optical disc drive being SATA I), the transfer rate of a 5400 rpm hard drive (the one that would be connected to that port) would still be lower than 150 MB/s.

Thank you both for your answers.