Not the best comparison test of 2013 v 2015 iMacs

Discussion in 'iMac' started by BKMK5, Nov 3, 2015.

  1. BKMK5 macrumors newbie

    Aug 6, 2010
    so after midnight on Friday I decided to compare the highest spec 2013 iMac with a 2015.
  2. fandangoguy macrumors newbie


    Nov 14, 2009
    Toronto -Canada
    hi there. I just found your comparison...did you use the 2013 for video editing or something graphics intensive? if so how did it compare to the late 2015? The cost of the i7 late 2015 is very high but of course has a better screen and specs but I wonder how behind the late 2013 is in real life applications like video editing. I saw that the SSD speeds in a late 2015 is 3 times faster. Does this mean that video rendering is twice as fast or so..or just marginally faster?
    Thanks for any feedback
  3. joema2 macrumors 65816


    Sep 3, 2013

    Disk drive speed has little impact on exporting common video formats like MPEG-2, H264, and MPEG-4. The I/O rate is not that high for these tasks, which anyone can confirm by using Activity Monitor or iStat Menus.

    Technically rendering means fully calculating any timeline effects or commands. However we sometimes loosely use "rendering" to mean exporting. In general you render an effect but you encode to a file or video stream.

    Encoding of common "long GOP" codecs like H264 is mostly CPU bound, since the I/O rate is not that high and the process cannot be meaningfully accelerated by the GPU.

    In general you want your media on an external drive, although for small jobs you could put it on the boot drive.

    I/O requirements significantly increase if using lower compression codecs like Red Raw or ProRes 422, and if handling multiple I/O streams in multicam timelines.

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