Can Someone Explain To Me Turbo Boost? How Is It Activated?

Discussion in 'MacBook Pro' started by Noerdy, Dec 17, 2016.

  1. Noerdy macrumors member


    Dec 13, 2016
    Everyone has heard of Turbo Boost, as it is one of Apples most prominently displayed specifications about their computers, but I have no idea WHAT exactly it is. Does it mean they can be overclocked to get to that speed? Does it mean when it is plugged in and has enough battery it will run faster? Do I have to manually turn it on? How? What triggers it? I have nearly zero understanding of what it is and how it functions, and would really appreciate some insight. :)
  2. /V\acpower macrumors 6502a

    Jul 31, 2007
    You have nothing to do.

    the CPU will over clock to TurboBoost speed if they need more power. The "normal" clock rate is lower so it uses less energy in "normal use". Turbo Boost will activate automatically as you demand more things from the CPU. Technically it can remain "turbo boosted" for as long as needed provided the cooling system inside the computer is able to keep up.

    So it also depend on the cooling system inside the computer.

    For example, the 13' base MBP have only 1 fan. If you are doing a demanding task on the CPU alone, it seem to be able to run at max Turbo Boost speed almost indefinitely. If you are doing a task that stress both the CPU and GPU at the same time, then the single fan can't keep up and the CPU will slow down do remain cool.

    The 13' TB MacBook Pro have 2 fans and they can max the CPU and GPU almost indefinitely, same for the 15' I assume.
  3. sentential macrumors regular

    May 27, 2015
    This isn't something unique to Apple, it is pretty complicated but I'll try to summarize it as short as possible. Essentially when a silicon chip is made its position and the grade of the wafer is done similarly to how diamonds are graded. Chips cut from the edge have higher impurities in the silicon than the ones in the center. So this concept of "overclocking" is not doing anything mysterious per say it is simply running the chip at it's natural ability rather than being grouped together.

    Once the wafer is cut they are binned based on grade, higher grade units are capable of running with a higher speed frequency than ones that are not. These grades are done in tiers of basically good, better, best and that is how they determine what chip becomes what speed, name etc.

    Mobile chips tend to be the highest grade since they need to perform under adverse conditions and Intel is taking advantage of that. So what they do is decide a bell curve of what the chips are capable of running and set standard deviations plus or minus of what on average each grade is capable of and bin them accordingly based on wattage.

    So if grade A or whatever they want to call it produces 100W of heat with 1 core and 1 thread at 4ghz but two is over 100 watts then again they being intel figured out what the next level would be at that wattage and so on.

    So when you fire up a game and it only needs one thread your CPU jumps to 4ghz, then 3.9, or 3.6 down to the "base" frequency of last resort before it takes critical action to shed heat and shut down to prevent from over heating. I know that's a bit wordy that is how it works.

    All of this is hard-coded to the chip's internal design and no changes have to be made for it to behave like this. The reverse is also used to save battery power so that the chip uses only what is necessary to run a program.

    The vast majority of time your chip will be in the 800-1200mhz range and will jump to 3.7/3.3 only when necessary to conserve power
  4. garyleecn macrumors 6502a

    Jul 25, 2014
    your base CPU clock is like the speed limit on a highway, that's the speed you should be driving without getting any problem.
    however, when there's no traffic ahead (temperature is relatively low), and doesn't seem to be any cop nearby (you have enough power supply to the CPU), then you can speed up a little. like driving 80 on a 60 road. however, you can't be driving at this speed for long, because you will soon catch up with other traffic ahead (reach temperature threshold), then you will have to slow down to the speed limit.
  5. mrex macrumors 68030


    Jul 16, 2014
  6. Noerdy thread starter macrumors member


    Dec 13, 2016
    I like car analogies. Thanks. :)
  7. Macalway, Dec 18, 2016
    Last edited: Dec 18, 2016

    Macalway macrumors 68030

    Aug 7, 2013
  8. Jefe's MacAir macrumors 6502

    Nov 21, 2010
    It's like driving your car down a flat highway at 65 MPH hour. As you approach a hill you begin to give the motor more fuel as to not slow down as you're climbing the hill. As you add more demanding tasks to your processor, it will increase capacity and speed as not to slow down the current tasks and maintain speed. And just like giving your car more throttle to get up the hill at your current speed and burn more gasoline, your computer will require more electricity to power the processor leading to shorter battery life on a single charge.

    What they really did was able to pace fast processors so that they don't use up energy unnecessarily. Turbo Boost just sounds so much cooler.

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