2011 MBP is either inefficient, or the iMac is overly efficient.

Discussion in 'MacBook Pro' started by revelated, Mar 6, 2011.

  1. revelated macrumors 6502a


    Jun 30, 2010
    To test processing efficiency - speaking strictly of the CPU, I decided to compare my 2011 MBP against the 2010 i7 iMac, just to see what the real difference would be when pushed to the limit. I ran a 25 minute encode through Adobe Premiere Pro - 1080p, 24fps, AVCHD. The results were rather interesting.

    First, CPU utilization. The MBP went to 100% utilization right after beginning and finished an hour later. The iMac never went past 65% utilization and finished 40 minutes later.

    Second, heat. The MBP got to 85C easily. The iMac never went past 65C. I'm wondering if the increased space, or the general design of the iMac - where heat can rise out of the top and away from the machine instead of downward like the MBP - helps on that.

    Question is why the MBP wants to use all cores to encode when the iMac doesn't, and why the MBP takes longer with more cores than the iMac with less. Curious outcome...not a negative, I'm actually intrigued by it.
  2. simsaladimbamba

    Nov 28, 2010
    The i7 iMac has four cores and can have up to 8 threads.
    The i7 2011 MBP has four cores and can have up to 8 threads.
    The i7 iMac's CPU is faster than the i7 2011 MBP's CPU.
  3. Hellhammer Moderator


    Staff Member

    Dec 10, 2008
    It's quite important to know what MBP you have. Most of the heat in MBP is designed to dissipate through the bottom so if that is blocked, then it will heat up. It also has less space so overall the cooling is better in iMac.
  4. Locodice, Mar 6, 2011
    Last edited: Mar 6, 2011
  5. superericla macrumors 6502

    Sep 27, 2010
    One good question is what macbook pro you're doing this testing with.
  6. revelated thread starter macrumors 6502a


    Jun 30, 2010
    Which is interesting, because under the same circumstances using Final Cut Pro, for example, the MBP will muscle it out faster than the iMac. FCP of course does not use all cores. So in other words, if the MBP is not being pushed, it ends up faster than the iMac. If the iMac is not being pushed, it ends up being faster than the MBP. Almost like running max cores actually slows it down, if that makes sense.

    2011 17" MacBook Pro 2.2. Which based on everything I read is actually supposed to be using a stronger CPU than Mac Pro, which I assume should be a stronger CPU than the iMac. Unless I misread the specs. That's why it was so intriguing.
  7. brentsg macrumors 68040

    Oct 15, 2008
    If the MBP isn't being pushed on all cores then the enhanced turbo mode will clock the 1-2 cores that are being used quite a lot more than in the past.

    If the MBP is being pushed on all 4 cores then the thermal situation may not allow turbo to do anything (so you're at 2.2x4). When the CPUs are pushed to their limits in their respective environments, there's no way that that 2.2 in the new MBP really outperforms the base Mac Pro. That will be a situational occurrence based on specific benchmarks and turbo.
  8. daneoni macrumors G4


    Mar 24, 2006

    Also also the cooling system in the iMac is superior to the MBP, Fans are larger and there's a larger surface area in general, they also use desktop drives which are always faster than their notebook counterparts. and there's a lot less nerfing (underclocking for heat purposes) in general.

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