Does the 3.8 Ghz MBP get noticeably hotter than the 3.5 GHz version

Discussion in 'MacBook Pro' started by alexor, Apr 30, 2014.

  1. alexor, Apr 30, 2014
    Last edited: Apr 30, 2014

    alexor macrumors newbie

    Joined:
    Apr 29, 2014
    #1
    I'm considering the 3.8 GHz as opposed to the 3.5 GHz, but if that causes the fans to kick in- or throttle considerably more often than the 3.5 GHz then I'll go for the 3.5 GHz. Intel puts both i7-4850HQ and i7-4960HQ at 47 W max TDP.

    I know from a friend who has the 3.5 GHz with the nVidia 750M that for low usage like internet browsing the laptop is silent, the fans are off - he has the model with the nVidia card.

    Anyone can comment on temperature differences between the two models?

    What about battery life?

    Many thanks in advance,
    Alex.
     
  2. yjchua95 macrumors 604

    Joined:
    Apr 23, 2011
    Location:
    GVA, KUL, MEL (current), ZQN
    #2
    I have the 2.6GHz i7-4960HQ, which TurboBoosts to 3.8GHz, and have noticed no difference whatsoever compared to my friend's i7-4850HQ in terms of battery life and temperatures.

    Both our rMBPs have the NVIDIA GPU.

    Battery life is also identical on both models.
     
  3. dmccloud macrumors 6502a

    dmccloud

    Joined:
    Sep 7, 2009
    Location:
    Anchorage, AK
    #3
    The temperature differences between the two models would be negligible at most. The TDP and thermal profiles are identical for the two processors, so there would be no noticeable difference between the CPUs themselves. The only way you'd see a difference is if one CPU had a dedicated GPU and the other did not. In that case, the machine with the dedicated GPU would probably run warmer when the dGPU is being used, regardless of which CPU it's paired with. Also, those are not considered 3.5 and 3.8 GHz parts - they are considered 2.4 and 2.6GHz parts - TurboBoost is an overclocked state, not the natural running state of the chips.
     
  4. MacSince1990 macrumors 65816

    MacSince1990

    Joined:
    Oct 6, 2009
    #4
    There's no such thing as a 3.5 GHz MBP. 2.3 GHz and 2.6 GHz sure. But not 3.5.
     
  5. Idarzoid macrumors 6502

    Joined:
    Mar 15, 2013
    #5
    There is, kinda, he's talking about the turbo boost. Some people go by the max turbo speed, some go by the standard clock speed.

    i7-4850Q has the clock speed of 2.3GHz but it can turbo boost to 3.5GHz.
     
  6. nando4 macrumors regular

    Joined:
    Mar 21, 2009
    #6
    Have discovered with the IVB CPUs that the Intel turbo boost algorithm will TDP throttle the CPU. How and when that happens will be determined by the individual CPU die itself. I noted considerable difference across three i7-3740QM units that were tested.

    The Haswell i7-quads are use the same 22nm tech, with minimal performance improvement. I'll take a calculated guess that they are going to behave in a similar way.

    REF: INFO: How to choose the most efficient 45W i7-quad

    If you wanted to get picky about it then you'd do the same Throttlestop testing as in the above link to get the most efficient CPU which would give you the best 4-core turbo-boosted performance.
     

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