Retina Macbook Pro Different Fan Speeds?

Discussion in 'MacBook Pro' started by boto, Jul 5, 2012.

  1. boto macrumors 6502


    Jun 4, 2012
    I know I am paranoid, but is it normal to receive fans speeds of around 2160 RPMs on the left and 2000 RPMs to the right in normal conditions, such as web browsing, email, and other minor usages? I want to clarify if my rMBP is defective or not, since I noticed classic MBPs have similar ranges. It seems I can never get both fans to rotate at the same level, it is always a 160 difference.

  2. Acidsplat macrumors regular

    Aug 12, 2011
    I may be wrong, but one fan is on the CPU and the other is on the GPU. If you get the processor to start working along with the integrated graphics, it'll need to cool more cause they're on the same die. Since the dedicated GPU isn't being used, it doesn't need to cool more than it does idle.

    The left fan covers the processor, so if the processor and/or integrated Intel graphics is working, it'll need to cool more than the GPU side on the right as its not being utilized.
  3. boto thread starter macrumors 6502


    Jun 4, 2012
  4. bizzle macrumors 6502a

    Jun 29, 2008
  5. Puevlo macrumors 6502a

    Oct 21, 2011
    It sounds like one fan is getting far less electricity than it needs to function. I'd suggest jump starting it with some jumper cables.
  6. GekkePrutser macrumors 6502a


    Aug 18, 2005
    Barcelona, Spain
    Not exactly, they're both on the same heatpipe in the retina model, but one is closer to the CPU and one closer to the GPU so in that sense it is right. But they should share the load more evenly than the previous model.
  7. markp99 macrumors member

    Jun 14, 2012
    New Hampshire
    The RPM mismatch drives the OCD side of me CRAZY! :D
  8. TheMacBookPro macrumors 68020


    May 9, 2008
    You can use smcFanControl and set it so the fan speeds are synced ;)

    I'm more worried about the fact that it can't seem to read the computer's temperature though.
  9. VFC, Jul 6, 2012
    Last edited: Jul 6, 2012

    VFC macrumors 6502a

    Feb 6, 2012
    SE PA.
    Since the heatpipe on the right side is attached to both the CPU and discrete GPU, it may be possible that some of the heat from the CPU/HD4000 chip is being absorbed by the GPU chip and surrounding circuitry before it gets to the right fan-sink. Just a theory.....

    The L/R fan speed on my cMBP is evenly matched in "normal" mode. I would expect that to be the case since the two heatpipes are exactly centered between the CPU and GPU.
  10. Tankmaze macrumors 68000


    Mar 7, 2012
    Sorry for bringing up old post.

    But just got the retina mbp, coming from cmbp late 2011. and indeed the right and left fan speed is not in sync. the left side is usually higher,
    so I guess this is normal ? appreciate it if anyone can reply or confirm. thanks
  11. Samuelsan2001 macrumors 604

    Oct 24, 2013
    It's deliberate to help direct air flow.
  12. Mnowell69 macrumors regular


    Jul 4, 2013
    Bedford, UK
  13. Tankmaze macrumors 68000


    Mar 7, 2012
    Awesome, didn't know about this.

    Thanks for the confirmation, I'm glad it is normal.
  14. snaky69 macrumors 603

    Mar 14, 2008
    Yes, you are paranoid. Yes it can happen under certain circumstances. The left fan is closer to the CPU and GPU and sometimes works harder than the right one.
  15. hiranya47 macrumors newbie


    May 12, 2017
    India, at a computer.
    You are not wrong.
    --- Post Merged, May 12, 2017 ---
    Yes this is normal.

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15 July 5, 2012