Transfer Rates between drives

Discussion in 'other software & services' started by beethoven, May 27, 2016.

  1. beethoven

    beethoven Registered Member

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    I wonder why transfer rates vary a lot between different drives. I can understand that USB 2 and USB 3 will influence transfer rates or transfers between internal and external drives will vary. What baffles me though is that sometimes the rate for the same type of operation (e.g. imaging) using the same PC and external drive on the same USB port with the same software program is quite different. What other factors play a roll here. If I do an image, a transfer rate of 44 mb/s is pathetic.
     
  2. xxJackxx

    xxJackxx Registered Member

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    Compression and encryption will affect the rate if they are being done as part of the process. Also, a file that is 100 MB will transfer faster than 1,000 files that fit into the same space due to the overhead of creating the filenames/allocating the space, etc.
     
  3. beethoven

    beethoven Registered Member

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    Jack, ok that makes sense but in the case of the images, I even noticed the varying rates without any of the settings being different. At times I aborted the operation, just pressed start again and my transfer rate suddenly went up 5 fold.
     
  4. zapjb

    zapjb Registered Member

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    Well since this isn't under backup, imaging & disk mgmt I'll say this. With a transfer the OS can get in the way. If I'm on a PC & a transfer is slow or I get an error. I'll boot a Linux LiveCD & make the transfer that way. And it'll usually fly.
     
  5. Brian K

    Brian K Imaging Specialist

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    beethoven,

    Which imaging app were you using? I'd also run chkdsk on both drives looking for bad sectors.
     
  6. beethoven

    beethoven Registered Member

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    Brian, I did not really keep any records - just happened twice over the last few weeks when I was doing more imaging than normal. I used macrium and noticed this on two different pc, though given that I am backing up to different internal and external drives, I don't have reliable records to document this further. Today's case was based on upgrading another Win 7 Pro to Win 10 and doing an initial backup of the new OS to an external drive. As this was a backup with keeping the settings/files, the resulting size of the drive was larger, so I was expecting a longer time. When Macrium indicated time to completion 3 hours and I saw the transfer rate, I got impatient and aborted. In this particular case I moved the external drive from one front usb slot to the next and all of a sudden the speed went to 300 mb/s. I suppose in this case it could be that one usb slot is dirty? I am fairly sure that at a previous time I did not even change anything, just cancelled the running backup and started a new one but this was on a different pc. I may run chsdsk tomorrow as you suggest but I had no indications otherwise that anything was wrong at either end.
     
  7. Brummelchen

    Brummelchen Registered Member

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    thats ok, i think
    usb2 standard is 11mb/s - 44 is faster that usb2 fast mode, but slower than usb3.
    my 1gbit lan is faster than 44mb/s :p

    speed is a matter of compaction, amount of files, read access, write access, antivirus and more.
     
  8. Rasheed187

    Rasheed187 Registered Member

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    I must say that I sometimes feel that transferring data between my internal SSD and HDD goes a bit slow.
     
  9. Minimalist

    Minimalist Registered Member

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    Antivirus scanning files during the transfer can also slow it down.
     
  10. beethoven

    beethoven Registered Member

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    Hmmm - can't say if AV was running at the time. It's possible. Chkdsk did not show any bad sectors on either the main pc or the attached external drive used yesterday.

    @ Brummelchen - I accept that certain variables will affect the speed, so I was interested to find out what the variables are. In the case listed though most of the variables were identical ( compaction, amount of files etc) so the variable affecting this should not be related to the backup itself but other factors. AV is something I had not thought about, could have kicked in at the time without my input.
     
  11. Brian K

    Brian K Imaging Specialist

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    That must be Mbits/sec rather than Mbytes/sec. I recall Macrium reports speed in Mbits/sec. I can't recall other imaging apps using Mbits/sec.
     
    Last edited: May 28, 2016
  12. beethoven

    beethoven Registered Member

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    Brian, the transfer rate is indicated as Mb/s by macrium. I am not sure what the actual speed is or which abbreviation is more appropriate but I noticed the varying speed indicated by Macrium. However they measure it, there was a big difference between one and the other.
     
  13. Brian K

    Brian K Imaging Specialist

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    beethoven,

    Mbits/sec is usually abbreviated Mbps

    MBytes/sec is usually abbreviated MB/s

    As you mentioned, Macrium use the abbreviation Mb/s but the number is actually Mbps. It is not MB/s. I think it is misleading. It certainly misled posters above.
     
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