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Why is Compressor way slower on 1 Mac Pro

354 Views 3 Replies Latest reply: Sep 7, 2013 5:56 AM by Bengt Wärleby RSS
Steve Garman Level 1 Level 1 (0 points)
Currently Being Moderated
Sep 4, 2013 12:17 PM

This is about Compressor 3.5.3 but it's not really about the version.


I have two identical MacPros 2,1 models both running OSX 10.6.8 and Final Cut 7.0.3 and Compressor 3.5.3.


The only difference in the machine is one has 20 gigs of ram and the other has 24 gigs.


I'm capturing BetaSP tape, 30 min loads, and then converting it to ProRes LT with Compressor. Same settings in both instances of Compressor.


I load 12 captures into one machine's Compressor and hit submit. It finishes in a little over two hours.


I load only 5 captures into the other machine's Compressor and hit submit. It finished in over 5 hours.


They are both 8-core machines with the same processors and are identical otherwise. I can't believe that 4 more gigs of ram would make that much difference.


Also they are sourcing off identical raids as well and writing back to identical raids.  Why is one machine so majorly SLOW!

iPad 2, iOS 5.0.1
  • Michael Grenadier Level 6 Level 6 (19,805 points)
    Currently Being Moderated
    Sep 4, 2013 1:16 PM (in response to Steve Garman)

    Have you done any speed tests on the raids?  I'd try swapping the raids between machines to see if that's where the problem lies.  Also have you installed and enabled distributed rendering using qmaster on both machines?

  • RatVega™ Level 4 Level 4 (1,855 points)
    Currently Being Moderated
    Sep 6, 2013 10:10 AM (in response to Steve Garman)

    Micheal has you looking in the right place.  Compressor uses very little RAM while processing but is very dependent on disk speed for good performance.


    Opening Activity Monitor while Compressor is encoding may reveal some useable info. I'd be looking at CPU usage and disk I/O speeds.

  • Bengt Wärleby Level 6 Level 6 (18,950 points)
    Currently Being Moderated
    Sep 7, 2013 5:56 AM (in response to Steve Garman)



    How much free space is there on the Main Hard Disks ?


    • Exactly the same ?


    • one is 5Gb or less the other 100Gb or more


    I never go less than 25Gb for work with interlaced SD-Video Quality


    think that about 4-5 times more will work OK for full quality HD progressive - may be ?


    What Processes are running in back ground ?


    • Time Machine

    • File Vault

    • Internet



    NON on my Video Mac


    else things that matters reg. speed and performance (for iMovie/iDVD - but are really general)




    • Minimum of 25Gb free space on Start-Up hard disk


    • No other programs running in BackGround e.g. Energy-Saver


    • Don’t let HD spin down or be turned off (in Energy-Save)


    • Move external/secondary hard disks that are not to be used to Trash - To be disconnected/turned off


    • Goto Spotlight and set the rest of them under Integrity (not to be scanned)


    • Set screen-saver to a folder without any photo - then make an active corner (up right for me) and set

    pointer to this - turns on screen saver - to show that it has nothing to show


    • No File Vault on - Important


    • NO - TimeMachine - during iMovie/iDVD work either ! IMPORTANT


    • Lot's of icons on DeskTop/Finder also slows down the Mac noticeably


    • Start a new User-Account and log into this and iMovie get's faster too - if a project is in a hurry


    • And let Mac run on Mains - not just on battery


    Yours Bengt W


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