2014 MacBook Air - actual i5 processor turbo frequency?

Discussion in 'MacBook Air' started by shoehornhands, Feb 22, 2015.

  1. shoehornhands macrumors regular

    Joined:
    Oct 9, 2014
    #1
    I purchased a 2014 MacBook Air with the stock i5 processor (suppose to be an Intel i5-4260U).

    Apple lists the processor speed as 1.4 GHz with a turbo of up to 2.7 GHz (same as Intel specs). However, I've never been able to get the processor clock to go above 2.4 GHz.

    I understand that the processor will only run at the max turbo frequency if temperatures allow for it (and in a notebook like the MacBook Air, it would likely start throttling pretty quickly). But even if I start a cpu intensive process (something like Handbrake that should use max turbo) straight out of an idle temp of under 40 °C, the processor only goes to 2.4 GHz.

    Anyway, just wondering if anybody else has experienced this.

    It's obviously not the end of the world (I know the MacBook Air isn't really designed for intensive CPU tasks) but it's a little obnoxious that the little extra "punch" isn't there when you need it.
     
  2. motrek macrumors 68020

    Joined:
    Sep 14, 2012
    #2
    I've noticed this too. I think 2.4GHz is the max frequency when 2 cores are loaded. Probably you can get to 2.7GHz if one core is idle. Handbrake uses both cores.
     
  3. cbautis2 macrumors 6502a

    Joined:
    Aug 17, 2013
    #3
    Run google octane benchmark and you'll see your GHz goes to 2.7 GHz briefly. 2 cores loaded is actually 2.4 GHz but one core partially loaded is 2.7 GHz. One core fully loaded will be 2.4 GHz since other tasks will be handled by the second core, making the GHz drop instantly from 2.7 to 2.4 GHz.
     
  4. motrek macrumors 68020

    Joined:
    Sep 14, 2012
    #4
    I just ran a process that maxed out a single core and my computer was idle otherwise. (Just a few % CPU usage.) My CPU should have been averaging close to 2.7GHz but according to Intel Power Gadget it never went above 2.4GHz. Strange. It was plugged into the wall and temperatures were low too.
     
  5. shoehornhands thread starter macrumors regular

    Joined:
    Oct 9, 2014
    #5
    Thanks guys, I appreciate the feedback.

    This is exactly what I noticed as well. I was originally thinking along the lines of what cbautis2 said (that 2.7 was tied to a single core).

    I tried out the Google Octane 2.0 benchmark and again, it didn't go above 2.4 even though the temp was only going up around 50 °C.

    I also tried out GeekBench (which I know tests both single-core and multi-core performance) and never saw it go above 2.4 GHz.

    I'm also using Intel Power Gadget to check clock speed (not sure if there could potentially be an issue with Power Gadget itself).

    It'd be one thing if the computer ran hot (I could see them releasing a firmware update reducing the turbo multiplier or something) but my MBA has plenty of temp headroom (correct me if I'm wrong but I believe these chips can get up around 90-100 °C before they throttle).

    Maybe it's just me but if a computer is specced for 2.7 GHz it would be nice if it didn't take a transit of Venus to actually run at 2.7 GHz.
     
  6. motrek macrumors 68020

    Joined:
    Sep 14, 2012
    #6
    Yeah this is false advertising. I've filed a bug with Apple.
     
  7. cbautis2 macrumors 6502a

    Joined:
    Aug 17, 2013
    #7
    I now noticed on my 2011 MBA that it doesn't go above 2.1 GHz (2.3 GHz max) where as my Surface tablet can easily Turbo to its Intel rated 2.9 GHz. I don't really mind it as I don't do CPU intensive tasks. Try Bootcamp and see if its the CPU or the OS X/EFI is the fault. I don't bootcamp on my MBA though.

    Intel Full Turbo.png
     

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