MBP: fan speed, external display, open or closed screen?

Discussion in 'MacBook Pro' started by thesheep, Aug 31, 2008.

  1. thesheep macrumors regular

    thesheep

    Joined:
    Mar 27, 2006
    #1
    My usual setup is a MBP with an external Cinema Display. I leave the lid on the notebook closed, and just use the Cinema Display. I also have an external HD plugged in via Firewire 800, and an Apogee Duet for audio.

    Recently I've become plagued by very fast fan speeds a lot of the time. When the fan is up around 5000 - 6000 rpm, it makes a lot of noise. I've tried all the usual stuff for resetting the OS, using SMCFanControl, etc. I'm not talking about excessive CPU usage - CPU is around 75% idle.

    I'm wondering what effect using the external display has, and what effect it has with the lid closed on the MBP. I've been trying it out in different combinations, and so far it seems that the external display adds quite a bit to the fan speed. It doesn't seem to relate directly to the temperature though. Maybe it is just set to run the fan about 1000 rpm faster when the external display is plugged in - perhaps due to extra load on the video card.

    I'd be interested to hear from other people who use a Cinema Display with their MBP, whether they have fan speed issues.

    I guess opening up the notebook lid might help with cooling, although it doesn't really suit me.
     
  2. thesheep thread starter macrumors regular

    thesheep

    Joined:
    Mar 27, 2006
    #2
    Yep, I'm finding that when my fan gets to around 5500 rpm, all I need to do is open the lid of the notebook, and it drops back down to around 3000 rpm.

    I'm sure that didn't used to happen.
     
  3. TraustiB macrumors member

    Joined:
    Nov 27, 2007
    Location:
    Reykjavík, Iceland
    #3
    I have a very very similar setup: 24" external screen, 1 firewire 400 and 1 firewire 800 drive connected, bluetooth keyboard and mouse.

    I only put this setup up 2 days ago and I've noticed the MBP runs quite a bit warmer than it did. On average it probably ran at aroun 45°C during normal "laptopy" use.

    I usually keep the lid open but turn the brightness all the way down so its black. I tried to use InsomniaX to be able to close the lid and still keep the computer running but that made the heat go all the way to 70°C which has never happened before. When keeping the lid open it hovers around 50 - 55°C with the fans going at 2000RPM.

    I always have Activity Monitor open and the CPU is at around 90% idle.. yet the computer gets hotter when the Display is attached and when its not the CPU is still 90% idle. Like you said, I'd recon it has something to do with the Graphics card.
     
  4. kolax macrumors G3

    Joined:
    Mar 20, 2007
    #4
    By closing the lid you are essentially making the laptop an oven - the head ends up being trapped, rather than being allowed to escape. If you want to have your MacBook Pro shut, then stack it vertically (so the exhaust is pointing into the air). That way the air rises and gets pushed out the exhaust, rather than being trapped under the closed lid.
     
  5. Eddyisgreat macrumors 601

    Joined:
    Oct 24, 2007
    #5

    ¬.¬

    I'm not sure if any of you are aware of the cooling design of the Macbook Pro, but its designed to operate effectively in "clamshell mode".

    Having the lid close will expose it to some heat, but its a computer, not an ice cube.

    The Hard disk will generate negligible heat when on, else everyone's left hand would burn on contact.

    Likewise the high voltage logic board components (GPU, CPU etc) are cooled by a very effective heat pipe system which cools off the components by routing the heat to two heat sink/fan combo's on opposite sides of the large vent on the back .

    [​IMG]

    [​IMG]
    In any case, computer components are designed to take some heat, nevermind the nvidia cards of death, and most of todays components are designed to shut down if thermal conditions reach a maximum. Any heat generated by your MBP with the lid closed will be negligible and the real heat will be exhausted from the back.

    My department runs 23"-30" displays in clamshell/workstation mode daily and most of them are data center guys who , i would hope, would know a thing or two about cooling.
     
  6. kolax macrumors G3

    Joined:
    Mar 20, 2007
    #6
    Okay, go ahead and run your MacBook Pro with the lid closed and start doing some heavy CPU work (such as encoding video that'll take a few hours) and I'd put money on the MacBook Pro cutting out because of heat.
     
  7. Eddyisgreat macrumors 601

    Joined:
    Oct 24, 2007
    #7
    I do gaming <in clamshell mode, max reso, AA,etc etc> but I guess I can scrounge up some HD renders in After Effects...again.

    Its all good. I just doubt that Apple would put it in their manual and give us fancy options to operate our macbook pro in full stealth mode without any interaction besides the insanely annoying power button.

    If it were really dangerous they would disable the option to utilize it in this mode, like they can when you remove power whilist in clamshell mode (the system will go to sleep and refuse to wake unless the LCD is up)
     
  8. aquajet macrumors 68020

    Joined:
    Feb 12, 2005
    Location:
    VA
    #8
    You've provided no evidence which suggests running in clamshell mode is bad practice. You completely ignore the fact that Apple has designed the computer to be operated in this fashion.

    Why should any of us believe you?

    :rolleyes:
     
  9. kolax macrumors G3

    Joined:
    Mar 20, 2007
    #9
    I'm not saying it is bad practise for normal use. However, if you are going to start doing CPU intensive stuff (encoding video that will take a few hours) and you keep it in clamshell mode, then it could cut out. I talk from experience - I left my MBP in clamshell mode while encoding video, and came back to find it had turned itself off. And in other times, when game playing in clamshell mode, the whole thing gets absolutely roasting, and I've had temperatures close to 95'C, where as low 80'C's with lid open.

    I'm not making your decision, just giving you my experience when doing heavy duty CPU stuff in clamshell mode.
     
  10. DoFoT9 macrumors P6

    DoFoT9

    Joined:
    Jun 11, 2007
    Location:
    Singapore
    #10
    MBP's hardware shutdown is around 110°C.

    there is literally no way to get your MBP to that temperature!!!

    i have had mine at 105°C (i forced the fans to stay turned off accidentally).

    running in clamshell mode will definately make it run hotter, youve even experienced this yourself!! if you cant put up with the noise open it up a few cm. if you can put up with the noise and the tiny (TINY) bit of extra deterioration on your components, keep it shut.
     
  11. kolax macrumors G3

    Joined:
    Mar 20, 2007
    #11
    You aren't familiar with the poorly applied thermal paste issues?

    I've been close to 100'C, and I haven't recorded the temperature my MacBook Pro cut out when in clamshell mode. It also cut out when playing likes of Need For Speed Pro Street with the lid open and in a cool room. That is the GPU and CPU pretty much being worked at 100%. Look at how thin the MacBook Pro is, and how poorly ventilated it is for intense power usage.

    I'd rather the design was sacrificed a little and more air vents placed (at the sides and bottom) to help increase the air flow.
     
  12. DoFoT9 macrumors P6

    DoFoT9

    Joined:
    Jun 11, 2007
    Location:
    Singapore
    #12
    the "poorly applied thermal paste issues" affect literally only 1% of the total MBP users, if you have a bad thermal paste job go do something about it.

    you have a santa rosa MBP.. i have a CD MBP (hottest of the lot) and i hit 80°C-85°C when under full load, with the fans not even at full RPM'age.

    even when gaming, like playing lego star wars, quake 4, cod2, and many other games i never get that hot.

    p.s. u cant measure what the GPU% is at so :p
     

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