Testing speed of int and ext hard drive MBP

Discussion in 'MacBook Pro' started by swingerofbirch, Oct 12, 2012.

  1. swingerofbirch macrumors 68040

    Oct 24, 2003
    The Amalgamated States of Central North America
    I have a mid-2012 13" MBP with built-in 750 GB HDD. I wrote in the SSD Buying Guide thread how I was thinking of upgrading to an SSD because the computer frequently is slow and I get a lot of beach balls.

    I then today also noticed that while moving a 25 GB folder of documents to an external USB 3 hard drive (my first time using USB 3), the transfer seemed to take just as long as with USB 2. I unfortunately didn't time the transfer, but I would guess it took over a half hour.

    I downloaded a program to try to test both the transfer rates via USB 3 and speed of my internal hard drive because I want to find out if something is wrong with the computer rather than the drive just being slow (as in the connector between the drive and the logic board). The program is called Blackmagic Disk Speed Test.

    I selected the external USB 3 disk first to test it and the results showed that the read/write rate was 135 MB/sec.

    The internal disk is more variable. I let it run for a while. It usually was 30 MB/sec, but it got as high as 47.5 MB/sec for write and 42.3 for read.

    That seems really low to me. But I'm not sure what it should be. But it seems as if the USB 3 drive is much faster than the internal drive, in spite of the external drive having a very slow transfer rate.

    Does anyone know what to makes of these numbers?

  2. PerformaGuy macrumors member


    Oct 5, 2012
    I think you have to take into account that a single large file can be copied faster than a large set of files (with the same total file size count). Does the disk test program you use differentiate between random and sequential copy test?
  3. swingerofbirch thread starter macrumors 68040

    Oct 24, 2003
    The Amalgamated States of Central North America
    True. The folder of files I sent over had a lot of individual files.

    The test, though, I believe uses an uncompressed test file that it writes to the disk.

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