The Notebook Review forums were hosted by TechTarget, who shut down them down on January 31, 2022. This static read-only archive was pulled by NBR forum users between January 20 and January 31, 2022, in an effort to make sure that the valuable technical information that had been posted on the forums is preserved. For current discussions, many NBR forum users moved over to NotebookTalk.net after the shutdown.
Problems? See this thread at archive.org.

    Question about SATA hdd.

    Discussion in 'Sager and Clevo' started by pasoleatis, Dec 28, 2009.

  1. pasoleatis

    pasoleatis Notebook Deity

    Reputations:
    59
    Messages:
    948
    Likes Received:
    0
    Trophy Points:
    30
    Hello,

    The hdds in in our laptops are SATA with a transfer speed of 3Gbps. When I copy form one hdd to another the maximum speed I get is 60 MB/s. This corresponds to USB or firewire speed (app. 450 Mbps). Why is this? I would expect for 3 Gbps a transfer speed of order of 1GB/s.

    PL
     
    pasoleatis, Dec 28, 2009
    #1
  2. theriko

    theriko Ronin

    Reputations:
    1,303
    Messages:
    2,923
    Likes Received:
    4
    Trophy Points:
    56
    1. 1B = 8b, so 3Gb/s = 384MB/s, not 1GB/s.

    2. 3Gb/s is the maximum throughput of the SATA II connecgtion interface, not the actual transfer speed. No mechanical drive can get close to that, they cant even max out SATA I (1.5Gb/s). The only way you'll see speeds nearing the limit is by hooking up multiple SSD's in RAID 0.

    3. USB has a max burst transfer speed of 480Mb/s (60MB/s) but that is not sustainable, so the actual performance is less. That is also why firewire (IEEE 1394 - 400Mb/s - 50MB/s) performs better for file transfer, due to 400Mb/s being a sustained data rate.
     
    theriko, Dec 28, 2009
    #2
  3. Dalantech

    Dalantech Notebook Consultant

    Reputations:
    149
    Messages:
    249
    Likes Received:
    0
    Trophy Points:
    30
    To add to theriko's excellent reply: The transfer rate of any device or buss is a maximum theoretical rate and it does not take into account "overhead" (data packaging, latency through the CPU, etc.).
     
    Dalantech, Dec 28, 2009
    #3
  4. rennyn

    rennyn Notebook Guru

    Reputations:
    23
    Messages:
    52
    Likes Received:
    0
    Trophy Points:
    15
    And to add further details, those speeds (60/sec) are about average for a laptop SATA drive.
     
    rennyn, Dec 28, 2009
    #4
  5. pasoleatis

    pasoleatis Notebook Deity

    Reputations:
    59
    Messages:
    948
    Likes Received:
    0
    Trophy Points:
    30
    Thanks for the answers. It is clear now.

    The 60MB/s speed it was the peak which I got only for large file.


    PL
     
    pasoleatis, Dec 29, 2009
    #5