i7 hyper thread vs actual 8 cores in real world practice?

Discussion in 'Buying Tips and Advice' started by GMunroe, Apr 13, 2012.

  1. GMunroe macrumors member

    Joined:
    Mar 24, 2012
    #1
    I have some confusion regarding the hyper thread i7 with virtual eight cores, vs an older Mac Pro with actual eight cores.

    I use mostly Flash CS5 for animation, exports to After Effects etc, and while viewing my iMac 3.4 i7 processor activity in iStat while using Flash, I see the technically eight cores appear, but only four cores of the i7 being engaged. If this is the case, would I be better served by a Mac Pro running, I assume, eight cores engaged all the time. Would this be the better performing machine in real world practice?

    I work with some fairly large files and due to CS5 having no workable export of Mov files in Flash, I usually have to export animations etc. to high res jpg and do the video export via After Effects. Just to prevent Flash dropping frames/frame rate when exporting directly from a timeline. So power is important. Something like the 3.2 dual quad Mac pros are quite old relative to the newer iMacs, but it isn't something I would be opposed to purchasing as well if I can understand the performance of the virtual cores vs the dual quads. Hex cores is far out of my price range, so I can't comment on those.

    If money wasn't a factor I would order the Mac Pro, and compare side by side with the iMac for my needs, and return the weaker of the two.
     
  2. coolspot18 macrumors 65816

    Joined:
    Aug 16, 2010
    Location:
    Canada
    #2
  3. 24Frames macrumors regular

    Joined:
    Mar 23, 2012
    #3
    A Mac Pro with 8 Physical Cores has 16 Virtual Cores.
    Try this site for After Effects performance tests (and other application performance tests) on all Mac models.
     
  4. jkmags macrumors member

    Joined:
    May 6, 2011
    #4
    When I was considering my last PC build I was comparing Intel vs AMD for performance. What I got out of it was Physical Cores > Hyper-Threading, basically if both processors had 4 cores 1 with Hyper-Threading and the other without you could see a 20% boost over the CPU without HT (is both were the same clock speeds).

    This also assumes your application can use the HTs, for example I use Handbrake and while ripping with the latest build I will see all 8 iStat cores running. When I'm running VMWare for my Windows application(s) I rarely see more than the 4 Physical Cores running. It all comes down to, can your App use HTs and if it does you can see a performance gain otherwise More Physical cores will give you the best performance.

    http://en.wikipedia.org/wiki/Hyper-threading
     
  5. paulrbeers macrumors 68040

    Joined:
    Dec 17, 2009
    #5
    If all else being equal, 8 "real cores" will always beat 4 virtual and 4 real cores. With that said, if comparing an i7 3.4ghz with 4 cores and hyperthreading, should be faster than say 8 cores based on the Core2* processors (i.e. 2006-2008 Mac Pros).
     
  6. spetznatz macrumors regular

    spetznatz

    Joined:
    Jan 5, 2006
    #6
    My MacBook Pro 2.2 GHz i7 16 GB is about twice as fast at rendering in Cheetah 3D as my eight-core 2.66 Ghz eight-core 16 GB Mac Pro 2006. I'm amazed at how fast the i-Series is.
     
  7. bvanlieu macrumors member

    Joined:
    Dec 28, 2008
    #7
    Which demonstrates nicely how microprocessor architecture should not be directly compared across families with attributes such as clock speed (Ghz) or HT.

    Given the same processor family, real cores will always beat HT. No one will argue that. Trying to compare a modern i7 with HT to a 1 or 2 gen old Intel non-HT processor is challenging and depends on the task.

    HT is useful when running multiple threads where during execution there are gaps in the pipeline, so another thread can use some of that time.

    Intel has done a nice job with this generation of HT (the first was pretty bad, I often disabled it on XEON servers as things ran 5% better without it). Of course in some of their line they boost cache size over an i5 which also gives a few % better performance in many tasks as well.

    - b
     

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