max fan speed on retina 15

Discussion in 'MacBook Pro' started by vbman213, Apr 8, 2013.

  1. vbman213 macrumors 6502

    Joined:
    Apr 13, 2010
    #1
    I've noticed that one of my fans maxes out at 5.5k RPM. I can't manually get it any faster. The other fan will max at 6k RPM
     
  2. craigy2302 macrumors member

    Joined:
    Feb 11, 2008
    Location:
    Scarborough, North Yorkshire
    #2
    Same here - so I presume it's normal.

    Right fan maxes out at around 5.5k
    Left fan 6k
     
  3. gr8tfly macrumors 603

    gr8tfly

    Joined:
    Oct 29, 2006
    Location:
    ~119W 34N
    #3
    I would also say it's normal.

    Here's a sample from my mid-2012 15" 2.7/16/768 (all CPUs at 100%):
    5935 RPM Left
    5503 RPM Right

    My 2¢ worth: just let the system handle the fan speeds and enjoy. The controller has algorithms which will keep temps and noise levels at optimum levels. When the system is doing light work, running the fans faster (I assume that's what you want the manual speed control for) isn't going to make much difference to an already cool machine and will needlessly use more power (I can only speak about my particular machine - it's always barely warm along the top of the keys and bottom.) When it is under load, the fans will increase speed above your set minimum anyway.
     
  4. bobcan macrumors 6502a

    bobcan

    Joined:
    Jan 8, 2007
    Location:
    Sunny but Cold.. Canada
    #4
    I do not know if it is related, but I remember reading something about a new asymmetrical cooling assembly/ fan design to keep noise down; perhaps the two fans are at different speeds to reduce sympathetic frequencies that would occur with BOTH running the same speed and through the same cooling tunnels.. Not sure if that is the case here, but would make sense to me, in an Audio Engineering kind of way.. :cool:
     
  5. gr8tfly macrumors 603

    gr8tfly

    Joined:
    Oct 29, 2006
    Location:
    ~119W 34N
    #5
    I briefly thought about that, but the difference of a couple hundred Hz could still be noticed as a beat, if the intensity were enough. I think it's more to do with the thermal distribution in the heat pipe. IIRC, the discrete GPU is on the same side as the faster fan.

    The asymmetrical design is done by placing the blades at varying spacing about the hub (some groups closer, some farther apart). When rotated, they cause air movement at different rates, the idea being to spread the energy across a wider range of frequencies. Someone (around the time of the rMBP launch) recorded the audio of both a rMBP and one with symmetrical blades. It's pretty easy to hear the difference, and if you have an audio app that can display a spectrum or waterfall display, you can easily see the difference in energy distribution.

    My previous machine, an Early 2009 17" UB, did have fans at the approx. the same speed, with just a few Hz difference. If there were an audible beat, I'm sure I would notice it (my ears are too sensitive at times…). I believe my earlier MBP and PB also ran at the same speed.
     

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