late 2009 quad core i7 performance

Discussion in 'iMac' started by MasonAtom, Aug 17, 2010.

  1. MasonAtom macrumors newbie

    Sep 1, 2004
    I recently bought a refurbed late 2009 quad core i7 iMac - I received it last Friday and have spent the better part of the last week migrating all of my software. I'm upgrading from a 1.8 GHz dual core G5, so I had to install new UB versions of all of my audio and website building software - took a long time to track down all of my serials and keycodes!

    Thus far I'm incredibly impressed with the machine - it is gorgeous and extremely responsive. Install times have been easily 5 to 10 times faster than on my G5. Launch times for Digital Performer and other audio programs that require plug-in scans are also about 6 to 8 times faster. I compared Handbrake encoding times on a few DVDs and it is a ridiculous gain - a 2 hour and 19 minute movie encoded in ~30 minutes vs. almost 4 hours on the G5. Audio performance monitor in Digital Performer was registering ~80% CPU usage on a 32-track song (with LOTS of plug-ins) on my G5 - the same file on the iMac barely moves the audio performance monitor (~ 5%).

    However, there is one thing that is puzzling me. Ripping mp3s from CD in iTunes has been a major disappointment - I'm only getting about 10X speed on the iMac, whereas I could get ~ 25X on my G5. The settings are the same (192 kbps) on both systems. Anyone know what could be going on here? Is there anything I can do to improve this?

    Thanks for any help or insight.

    oh - one last thing - my G5 system has 6.5 GB RAM and I'm currently operating on 4 GB RAM on the iMac (but will install another 8 GB today). Maybe the difference in RAM is the culprit here?

  2. aliensporebomb macrumors 68000


    Jun 19, 2005
    Minneapolis, MN, USA, Urth

    The superdrive might not be so super?

    I've heard the mechanisms aren't as stellar as the ones in the G5s.

    My 2009 i7 has 12 gigs of ram and my MP3 encoding is as fast as 13.5x at the beginning of the CD (track 1) but as it gets to the end (track 12 on a recent disc) it goes as fast as 22x. But not much faster.

    This is using 'iTunes Plus' setting.
    There was no difference in encoding speed using MP3 192 kbps.

    I believe it's a mechanical issue.

    Re-encoding one of the encoded tracks had it encoding at 40x speed and that was on a drive not directly connected to the computer - I suspect encoding one that is saved to the internal drive would be faster yet.
  3. CubeHacker macrumors 65816


    Apr 22, 2003
    This occurs because Apple uses slim laptop optical drives, and you are comparing it to a desktop optical drive which has the ability to spin the disc much faster.

    If you copy the contents of the CD to your hard drive (such as WAV format, or even the pure CD audio), and THEN use itunes to convert the files using your hard drive as the source instead of the CD, then i'm sure you will see encode times that are easily 5x faster than what you are seeing. Unless of course iTunes is limited to only use a single core =)
  4. MasonAtom thread starter macrumors newbie

    Sep 1, 2004
    thanks for the response guys - makes sense - not sure why I didn't think of that.


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