FCPX, when is GPU when is CPU ?

Discussion in 'Mac Pro' started by rueyloon, Jul 30, 2014.

  1. rueyloon macrumors regular

    Sep 24, 2013

    hi, after a couple of weeks of reading up, can anyone verify this for me ?


    GPU is mainly for final rendering, and it can cut down the time required.
    But what about during editing ? it is mainly CPU when it is generating previews on the fly ?

    I've been trying to get a comparison between D500 and D700 but after 7 months of the Mac Pro, there still isn't a definitive comparison for FCPX workflow. Most of the advice I get is "get the D700 because GPU isn't upgradable..."

    I'm somewhat stuck due to my own experience of upgrading the GTX120 to GTX670, it sped up rendering by 30% but does almost nothing for responsiveness during editing.

  2. stefmesman macrumors 6502

    Jun 25, 2010
    Fcpx is very well written. The gpu wil be used during the entire process of the edit from effects in the viewer. As the viewer preview itself. The gpu wil kick in multiple times during edit. There is no exact way of knowing what the gpu is doing when.
  3. Prince134 macrumors 6502

    Aug 17, 2010

    If you upgraded from gtx120 to hd7970 for fcpx, you wouldn't say that.
    Fcpx is optimized with openCL GPU computing.
  4. rueyloon thread starter macrumors regular

    Sep 24, 2013
    how is your experience with the hd7970 ?
  5. N19h7m4r3 macrumors 65816


    Dec 15, 2012
    It's essentially a Single D700, but a tad faster.

    Compared to the GTX670 it's in a league of its own for OpenCL and FCPX performance.

    Note the R9 280X is the 7970Ghz edition. Both faster than the D700

    They're vastly better for FCPX and OpenCL

    You also need to remember responsiveness is also very much determined by disk speed. Especially for quickly scanning/moving the head through projects. You can easily experience lag and dropped frames due to a slow disk.
  6. poematik13 macrumors 6502a

    Jun 5, 2014
    Most of the visible "performance" that you feel during fcp x, i.e when you scrub through the timeline and look at footage etc, is determined by your disk speed.

    the GPU is used heavily during footage export and effects rendering so thats where you'll notice it the most. the CPU is also used most of the time in general throughout the app.
  7. rueyloon thread starter macrumors regular

    Sep 24, 2013
    so assuming if I upgrade my oMP the octo 3.33 with a better graphics card, I will only see improvements in final export or render right ?

    It should not do much for editing, I will have to wait for the red line to finish before I can view the effects as the computer is still not fast enough to generate the previews on the fly ?

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