rMBP left fan running slightly faster than right?

Discussion in 'MacBook Pro' started by KitzelFox, Jul 9, 2012.

  1. KitzelFox macrumors newbie

    Jun 22, 2012
    I have noticed that by monitoring iStat, the left fan of my base model rMBP typically runs at 150-200 rpms more than the right fan. I was wondering if this was an issue or potential issue. So far I don't think I have had any problems cooling the machine, but I really don't know if this is normal or not. I have noticed it in all situations, on and off the battery, on my lap and on my desk. It doesn't really seem to matter what the situation is, it does it when it's cool and it does it when it's hot.

    Thank you everyone and I apologize if this is just a silly question. :rolleyes:
  2. fizzwinkus macrumors 6502a

    Jan 27, 2008
    I don't know, but my guess is that the gpu sits close to the left side of the heat sink while the CPU is centered. The temps on that left fan will be higher than on the right fan and it will need to spin faster.
  3. jav6454 macrumors P6


    Nov 14, 2007
    1 Geostationary Tower Plaza
    If it bothers you, just set both fans to the same speed using SMCfancontrol.

    However, the left fan might spin faster due to GPU cooling as well.
  4. trsblader macrumors 6502

    May 20, 2011
  5. cjw2222 macrumors newbie

    Aug 16, 2011
    I noticed this too. I inquired and it is completely normal, has to do with the layout of cpu and gpu
  6. doh123 macrumors 65816

    Dec 28, 2009
    a couple hundred RPMs probably doesn't matter.

    I suspect they did this for the same reason they have the asymmetrical blades... so each fan is making a wide range of noise at a slightly different frequency, making it less annoyingly noticeable to the ear.
  7. korbearus10 macrumors member

    Jun 27, 2012
    Completely normal. Mine does that. 2000RPM/2150RPM.

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