CPU @ 100% on iStat Menus

Discussion in 'Mac mini' started by opinio, Mar 26, 2013.

  1. opinio macrumors 65816

    Mar 23, 2013
    When iStat menus shows my 2012 mini i7 2.6 ghz running at 100% is it running at 2.6 ghz or the 3.6 ghz turbo boost speed. If it is running at 3.6 at 100 % then why bother referring to it as 2.6?

    Can one of the tech minded explain this?
  2. paulrbeers macrumors 68040

    Dec 17, 2009

    I don't use iStat, but I assume what you are doing is something single threaded (i.e. iTunes) and maxing out 1 core. When only 1 core is maxed out, the i7 can run up to 3.6ghz. However, if all 4 cores are maxed out it can only do 2.6ghz. That's why it is a 2.6ghz processor because if you completely max out the processor it will only run at 2.6ghz.

    Hope this helps.....

    Google is your friend which would have saved you time and effort:


  3. opinio thread starter macrumors 65816

    Mar 23, 2013
    Thank you. That makes sense now. I thought the 4 cores could max out to 3.6.

    It sounds like it sort of has the ability to run like a dual core 3.6 (in the case of two cores maxing out) or a quad core 2.6 (in the case of 4cores maxing out).

    That's my non tech way of thinking about it.
  4. paulrbeers macrumors 68040

    Dec 17, 2009
    Pretty much. Basically one core can do 3.6, then two cores something like 3.3 (there's actually a table somewhere that actually spells it out), then 3 cores maybe 2.9 and all for at 2.6. In a lot of ways by saying it's a 2.6ghz part instead of 3.6, they are being more truthful in their advertising (or being conservative to avoid lawsuits). It all has to do with the fact that if you are only using one core, then that one core can "overclock" to 3.6 since none of the other cores are giving off any heat and thus is staying under the 45w TDP. But then if two are giving off heat, then it can't "overclock" as much, etc. etc. etc....
  5. CIA macrumors 6502a

    Jun 17, 2003
    Correct me if I'm wrong, but I also think there's a little bump in speed if all 4 cores are in use but not at 100%. Basically it dynamically bumps the speeds while staying below the TDP value of the proc.
  6. paulrbeers macrumors 68040

    Dec 17, 2009
    It depends. Say if 1 core is at 100% doing one task, and another is doing some remedial task and is only running at 10%, then yes I believe the processor will increase it will turbo somewhat so that task that is maxing out core 1 completes at least somewhat faster. However, if all cores are being stressed but not maxed (say 50% or better) then no I do not believe there is any turboing occuring because all the cores are putting off considerable amount of heat.

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