Why is the clock speed of the 13" MBP greater than the 15" & 17"?

Discussion in 'MacBook Pro' started by mrsir2009, Feb 26, 2011.

  1. mrsir2009 macrumors 604


    Sep 17, 2009
    Melbourne, Australia
    Why is the clock speed of the 13" MBP greater than the 15" & 17"? The high end 13" is 2.7 Ghz while all the 15" and 17" models are 2.3 Ghz... And the 15" and 17" are Quad Core while the 13" is only Dual Core. Whats up with that?
  2. Jarg macrumors newbie

    Jan 7, 2011
    Huntington, WV
    The 15 and 17 inch MBPs are quad cores, meaning that they run 4 cores instead of the 2 cores like the MBP 13". Running more cores, means more heat and power consumption, so they are clocked at a slower rate to prevent overheating and 1 hour battery life all the time.

    The 13" has dual core options because it is smaller and probably can't handle the heat generated by the quad cores like the larger models can. Its also important to note that quad core CPUs are much more expensive than dual cores, which is why the 15" base model is several hundred dollars more than the 13" base model.

    Hope this answers your question.

    Edit: Don't think that the quad cores are slower because they are clocked at lower speeds. With turbo, a quad core has the potential to be sped up the same or even greater speeds than the dual cores. Turbo does take more power and makes more heat, but if you doing things that require a quad core, then the added speed is worth the cost.
  3. alust2013 macrumors 601


    Feb 6, 2010
    On the fence
    You basically just answered your own question. The 13 has a higher clock because it's dual core, and it uses dual core because that uses less power and produces less heat, which is needed for the smaller computer.
  4. badpinoy macrumors regular

    Oct 25, 2007
    lets not forget that the since the cores take advantage of hyper threading. So now your two core becomes four and the quad (four) core becomes eight.
  5. Sneakz macrumors 65816


    Jul 17, 2008
    Toronto, Ontario, Canada
    Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_2_1 like Mac OS X; en-us) AppleWebKit/533.17.9 (KHTML, like Gecko) Version/5.0.2 Mobile/8C148 Safari/6533.18.5)

    Cores aren't the same as threads.
  6. mrsir2009 thread starter macrumors 604


    Sep 17, 2009
    Melbourne, Australia
  7. serenesam macrumors member


    Jan 15, 2011
    I don't know why some people keep focusing on clock speed when it is only one factor determining the overall speed of the processor. For example, an intel core pentium clocked at 2.2 ghz is going to be slower than an intel core duo 2 clocked at 2.0.

    To address your question, I believe the 15 and 17 inch models are faster:

  8. badpinoy macrumors regular

    Oct 25, 2007
    okay for each core it now has now two "virtual cores"
  9. c1phr macrumors 6502

    Jan 8, 2011
    Technically even that isn't true. A thread only works when the CPU is waiting for data for a separate thread (basically, it goes a bit more in depth than this).

    As far as which will be faster: the Quads will be faster (15" & 17") since they can turbo two cores to speeds greater than the 13". I don't think the difference will be massive, unless you are pushing your core really hard.
  10. csnplt macrumors 6502


    Aug 29, 2008
    Chicago Area
    Both will be more than fast enough for most "general computing." Keep in mind that the quad core models can still turn off two of their cores (or more) if they're not needed, allowing the remaining two cores to increase their clock speeds. If only one core is active, the quad core 2.3 GHz model can actually scale up to 3.4 GHz (slightly less for the 2.2 and 2.0 GHz quads).

    The dual core models can also take advantage of Turbo Boost, by the way.

    Anyway, the quad cores should always be faster than the dual cores (due to Intel's Turbo Boost). Basically, in situations where you'd need 4 cores, the quad cores are much faster (up to around 2x faster in some cases), and in other situations where you'd only need 2 cores, the quad cores can still turbo boost 2 of their cores up to the same frequency as the dual core processor would be clocked at.

    Sorry for the long reply. Hope it's helpful. :)

    EDIT: By the way, unless you have specific tasks that benefit from having 4 cores (such as movie encoding, for example), don't make your buying decision based on the processor. Choose based on form factor (or graphics, where the performance gulf between the 15'' / 17'' and the 13'' is much wider).

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