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Thread: Time Needed to Copy 14gb to external USB Harddrive

  1. #1
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    Wink Time Needed to Copy 14gb to external USB Harddrive

    How long should it take to copy 14gb to an external hard drive, using a USB 2.0 connection?

    Thanks,

    Robert

  2. #2

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    Depends on the speed of the drive, how fragmented it might be, size of the files... Around an hour, maybe more. Transfer rate for USB2.0 should be around 30Mbps, so.... if I'm remembering right....

    14Gb * 8 bits * 1000000000 / 30000000 = 3733 seconds = 62 minutes?

  3. #3

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    Quote Originally Posted by eolesen View Post
    Depends on the speed of the drive, how fragmented it might be, size of the files... Around an hour, maybe more. Transfer rate for USB2.0 should be around 30Mbps, so.... if I'm remembering right....

    14Gb * 8 bits * 1000000000 / 30000000 = 3733 seconds = 62 minutes?
    USB 2.0 got 480Mbps transfer rate, that is 480 / 8 = 60 MB/s !
    Which in turn means that for 14GB, i.e. 14,336MB, you would need exactly 239 seconds, i.e. just about 4 minutes to copy the files.

    With USB 1.0/1.1 you would need 159 minutes as a minimum.

    This applies to large files only, however, e.g. DVD images, which are copied onto HDDs (faster than most thumb drives).
    Small files will take much longer to write, esp. on thumb drives.

    I know what I'm talking about since I'm constantly backing up all my files - including newly installed rolling stock and routes, i.e. my whole MSTS installations - via USB 2.0 thumb drives (as a transport means from one computer's HDD to another computer's HDD).
    https://www.trainsim.com/vbts/signaturepics/sigpic164208_1.gif

  4. #4

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    At least my formula was correct... At 480, you're right -- 3.98 minutes.

    I just ran a 1Gb test file, and it took around 45 seconds. on my drive. Using the formula, it should have taken 29 seconds, so your mileage can and will vary depending on the condition and speed of the drive.
    Last edited by eolesen; 01-06-2012 at 11:27 AM.

  5. #5
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    The speeds (throughput) you guys are all talking about are theoretical ideals. There are many factors that will cause the actual throughput to be slower than the advertised amount.

  6. #6
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    Quote Originally Posted by jovet View Post
    The speeds (throughput) you guys are all talking about are theoretical ideals. There are many factors that will cause the actual throughput to be slower than the advertised amount.
    Joseph:

    Good point. I did some basic research, and found all kinds of numbers for USB 2.0 throughput, most significantly slower than advertised.

    One issue is whether the USB connection is via the motherboard, or a USB hub, with the MOBO connection being faster.

    To clarify - I want to backup a 14 gigabyte Steam/RS 2012 directory onto an external hard drive, using a USB 2.0 connection. My Western Digital external HDD isn't cache specific - WD says as much, so let's assume an 8mb cache. I'm using Microsoft Sync Toy 2.1 to accomplish this task.

    Further, assume the throughput is 1/2 the advertised maximum. How long should this take?

    Thanks,

    Robert

  7. #7
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    Quote Originally Posted by ForestHIllsRob View Post
    Further, assume the throughput is 1/2 the advertised maximum. How long should this take?
    Based on the values figured above, I'd reckon 10-25 minutes for continuous data flow.

    But there are even more factors. Lots of little files are a lot slower to process than a few large files. Essentially the data stream stops and starts several times a second, for each file. Plus, the disk's index has to be updated for each file. Since MSTS is a lot of little files, then it's going to take a fair amount longer than "ideal" or "corrected" throughput estimates.

  8. #8
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    FYI: I run a daily Norton Ghost of my system to a 1TB external USB 2.0 drive. Just a normal cheap drive, nothing fancy. It makes a 20GB image in about 50 minutes.

    Edit: Oops. I forgot I had that drive hooked up via eSATA instead of USB (it can be either). I'll copy the file to a USB drive and report the results later. In the meantime here are some benchmark results for various drives:

    Here's an identical drive hooked up via USB 2.0:
    capture_005_06012012_163634.jpg

    This one is of the external drive in question, hooked up eSATA:
    capture_001_06012012_161220.jpg

    In case you are interested, here's an ordinary SATA drive:
    capture_002_06012012_161610.jpg

    And just for reference, here's my system disk (SATA 3.0 SSD):
    capture_003_06012012_161946.jpg
    Last edited by stresstool; 01-06-2012 at 07:46 PM.
    Dave

  9. #9
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    Quote Originally Posted by stresstool View Post
    I'll copy the file to a USB drive and report the results later.
    It took ~12 minutes to copy a 20GB file to my USB drive which is expected at ~29MB/sec.
    I don't have a 14GB directory anywhere. My RW directory is ~30GB. I did an rsync of it to the USB drive and it took 1 hour and 3 minutes. If it scales linearly, yours should take 14/30 (~47%) of that or a little over 1/2 hour.
    Dave

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