Macbook pro 2018 heating issues

Discussion in 'MacBook Pro' started by AzizJalel, May 28, 2019.

  1. AzizJalel macrumors newbie

    Joined:
    May 28, 2019
    #1
    Hey guys,
    I've bought my Macbook pro 15 " 2018 last December and I'm a little bit disappointed to be honest.

    Here are some strange things that caught my attention :
    - CPU temp is peaking whenever I'm booting up the Macbook (It goes up approximately to 70-80°C then decreases to 40 - 50 °C after a few seconds, I'm using iStats menu to track it and I can tell it's not a displaying bug since I can feel the macbook being hot when I touch the metal near the screen)
    - Fans are constantly running near 2000 rpm (Whatever the temperature is, both of my fans are running between 1950 - 2100 rpm ! Even if the temperature reaches 80°, they keep running between 2100 - 2000 rpm , I've tried resetting the smc but the problem persists)
    - Also , another thing is that whenever I open an application, CPU temp peaks then gradually decreases, is that normal ?


    Thanks, looking forward to solving these problems ^^'
     
  2. leman macrumors G3

    Joined:
    Oct 14, 2008
    #2
    All of this is perfectly normal. Then you CPU is actively doing work, it's obviously going to heat up. Booting up is a CPU-intensive process. Launching apps is a CPU-intensive process. With fans, 2000RPM is completely silent and also normal. The fans will ramp up if your computer needs them.

    So basically, your sorry is like seeking medical advice with "guys, I noticed that my heart is beating faster when I walk up the stairs, am I going to die now?" ;)

    My advice: stop looking at iStats. These tools are useful when you want to optimise your machines performance, test its limits, or diagnose a problem (such as computer being permanently hot, or loud or sluggish). As long as your computer works and you have no complaints about its actual functionality, all these stats are meaningless.
     
  3. jerryk, May 28, 2019
    Last edited: May 28, 2019

    jerryk macrumors 601

    Joined:
    Nov 3, 2011
    Location:
    SF Bay Area
    #3
    15 inch MacBooks have constantly run their fans since the first Retina MBP. 13 inch used to stop and start fan. Not sure if the new quad core 13" units do.
     
  4. William Payne macrumors 6502a

    Joined:
    Jan 10, 2017
    Location:
    Wanganui, New Zealand.
    #4
    One thing I think is important to remember is that there is a crap load of aluminium in the body of a MacBook Pro. Aluminium is just a light weight heat sink. When you feel the chassis getting hot, what you are feeling is the Aluminium taking heat away from the internals.

    Like touching something metal that's been out in the sun on a really hot day. Irrelevant of the temperature it is going to be hot.
     
  5. leman macrumors G3

    Joined:
    Oct 14, 2008
    #5
    It has been the case before retina models as well. CPUs are more power-hungry now than 10 years ago (2009 MBP had a 35W CPU in the 17", now its 45W+ in a 15"), and they also overclock on demand, resulting in frequent quick burst of heat. You just can't cool this down passively, unless you have a large heat exchanger. Heat management in 2019 is much more complicated than it was in 2008.
     
  6. AzizJalel thread starter macrumors newbie

    Joined:
    May 28, 2019
    #6
    [​IMG]

    Here what happens guy when I boot up my macbook .
    It returns after few seconds to normal temperatures.
    What do you think ?
     
  7. raymanh macrumors member

    Joined:
    Aug 27, 2017
    #7
    I always see issues with fans on here but I don’t understand why. I’ve got a 2016 MBP 13 without the Touch Bar and the fans never come on (I have macs fan control open all the time to monitor temps and fans). Even when I’ve got word, excel, notes, mail and safari with 30 tabs open and on YouTube the fans just don’t come on and the temps are always reasonable. Why is this? Did I just get lucky? (I don’t disable the fans or anything like that in on macs fan control)
     
  8. maratus, May 28, 2019
    Last edited: May 28, 2019

    maratus macrumors 6502a

    maratus

    Joined:
    Jun 12, 2009
    Location:
    Canada
    #8
    I've been using SMC fan control for years and always set up both fans to speed up from 2000 rpm @ 40...45C to 5500/6000 rpm @ 85C. Default fan curves prioritize noise over cooling and enclosure temperature. I don't want for the fans to idle while CPU reaches 90C under load.

    There's a massive difference in heat between a 15W low power dual-core and a high-end 45W quad-core CPU with discrete graphics card.
     
  9. leman macrumors G3

    Joined:
    Oct 14, 2008
    #9
    I think that you are trying very hard to find problems where there are none. This level of anxiousness can’t be good for your health.
     
  10. raymanh macrumors member

    Joined:
    Aug 27, 2017
    #10
    But shouldn’t the 45W quad-core have to work less hard compared to my 15W?
     
  11. leman macrumors G3

    Joined:
    Oct 14, 2008
    #11
    Why would you think that? It will get stuff done faster, but it will also consume more energy. Anyway, it’s more complicated nowadays, since a 15W CPU will draw far more than 15W for short periods of time.
     
  12. maratus macrumors 6502a

    maratus

    Joined:
    Jun 12, 2009
    Location:
    Canada
    #12
    Only if you have the same exact workload that's limited by the application. In that case whichever processor is more energy efficient remains cooler. Both processors will do the same task equally fast. And it's most likely that there simply is no significant difference between either 15W or 45W chips that are manufactured using the same technological process.

    But once you do something that takes as many resources as it can, the 45W quad-core gets fully loaded, completes the job much faster and dissipates much more heat while doing it. Perfect example – video encoding, when it could be 2 hours vs. 5-6 hours difference, and it uses up 100% of the CPU resources.

    Since we judge our laptop thermals based on peaks and not average power, higher performance unit will always appear hotter (unless there's a significantly more capable heatsink / fan combo which isn't the case with 15" rMPB)
     

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11 May 28, 2019