Fans run even when cpu temp has lowered to 50C

Discussion in 'MacBook Air' started by stakis, Apr 2, 2008.

  1. stakis macrumors member

    Oct 25, 2007
    So was using Ichat the other day running a full screen chat, and I saw the temp of the CPU rise to about 65C and the fans started spinning up 6200.... That was understandable as the CPU was under load... but after I closed the ichat down, the CPU temp dropped down to about 50C but the fans stayed at 6200 for a long period of time.... probably about 10 minutes or so... then they slowly crepted down to 2500....

    anyone else experience a very slow response from the fans???
  2. Particular macrumors member

    Nov 28, 2007
    How the hell is this understandable? This is 2008, doing video chat is not supposed to be hardcore stuff. This is a $2000 computer, and I don't expect it to sound like this with its 6200RPM fan when I want to actually do something. Steve Jobs proclaimed the innovation of the MacBook Air was its ability to dissipate the heat generated by the full blown CPU - the reason why these computers usually use ULV in the first place...He said the MBA had the thermal envelope to handle it, but he is full of ****. The fan on the MBA is a joke and completely ruins the experience of it. Nothing more embarassing than in the middle of a lecture your brand new $2000 starts sounding like a Hoover Vacuum its just pathetic.

    And just like you they linger on 6200RPM. You have to put it in standby and wake it backup and then everything is ok. Just pathetic.
  3. mcvaughan macrumors 6502a

    Aug 9, 2007
    Houston, TX
    It's a rev 1 product, and they tend to have bugs. These bugs will eventually be sorted by Apple, but it can take time. Unfortunately, it's the life of an early adopter. For me though, it hasn't been anywhere as bad as it's been for others.
  4. aristobrat macrumors G5

    Oct 14, 2005
    Mine seem to spin down proportionately to how warm the bottom of my MBA is, not by how warm the CPU is.

    Depending on that, it can either be a slow response or a quick response.
  5. ayeying macrumors 601


    Dec 5, 2007
    Yay Area, CA
  6. stakis thread starter macrumors member

    Oct 25, 2007
    Hey guys thanks for the reply,

    I'll keep an eye on the enclosure fan next time to see if it is that that is making the fans stay on....

    as for USB devices, I'm not using any when I experience this.

    I'm going to try a few things before I contact apple.... I was thinking of getting the computer really hot, and then just holding it upside down to cool faster and see if it makes a difference, as the desk gets hot as the computer gets hot, so I'll see what that does for me.

    if you have any other ideas...

    as for the me not accepting this... I see where you're coming from, but really this is a first for the notebook industry so I'm a little lenient when it comes to minor issues like this... I don't expect a Rev A to be absolutely perfect, just as functional as possible....

    and remember its hard to have a "Perfect" product... they all have their ups and downs.... luckily the MacBook Air has way more ups than downs for me.
  7. MarkF44 macrumors member

    Apr 6, 2008
    6200 Rpm


    I experience the same, once you have used a heavier application like open office, amsn, or safari on heavy pages, the fans run at 6200 RPM and even if you close all applications, it remains for ten minutes.

    it is quite annoying to see most of the time the CPU between 50 and 60 °C and the fans at 6200 RPM with less 10% CPU used by both system and user
  8. rom macrumors regular

    Jun 7, 2006
    Remember that the enclosure is aluminum, which conducts heat better than plastic (keeps heat as far away from the processor as possible) but does not cool instantaneously. Unless there is a way to super-cool it, then you may need to wait a couple of minutes for the temps to drop (and so will the fans).

    Another factor is the temperature of the environment. In 32C environment, with no air conditioning, the MBA hovers at 6000rpm and 48-55C. Shoots up rather swiftly and cools down in 10 minutes or more.

    I do not think that there is anything wrong with the MBA except for the slow HDD rpm and the slow processors.
  9. MarkF44 macrumors member

    Apr 6, 2008
    Well, I agree with the latency to cool down but I disagree with the "no issue" because the MBA sometimes stay one hour with 42°C for the case and 55°C for the CPU and sometimes not with exactly the same temperatures, I can't find any explanation to this except a sensor defect or a SMC defect, both are unacceptables.

    HDD and processor are quite fine for a '"classical" notebook use IMHO. Till the 6200RPM issue I really enjoy this laptop, very nice screen, case, keyboard.
  10. rom macrumors regular

    Jun 7, 2006
    I forget to add - the fans rev up when you are using your MBA whilst plugged in. Also, the small footprint makes any change in temperature from the CPU, HDD, enclosure, battery affect the overall performance. Remember that the MB and MBP have far more space for air to flow freely.

    Curious, though - I wonder how many fans the Lenovo Thinkpad X300 has.
  11. dennarda macrumors newbie

    Jul 8, 2007
    I have noticed this as well. It seems as though the fans are slow to react to rising temperatures and g from 2500 to 6200 to 2500 but rarely sits somewhere in between. It only ramps up when the processor is already stinking hot and only slows down after it has reached an icy cold. I hope this is an early revision glitch, but perhaps it is an attempt to converse battery life.
  12. aristobrat macrumors G5

    Oct 14, 2005
    That's why I don't think the fans are being controlled by processor speed alone. My MBA fans seem to ramp up/down roughly according to how warm the bottom of the notebook is, not what the current CPU temp is.

    For example, my CPU can be doing pretty much nothing when my MBA is hooked to a 24" monitor, but the bottom of the notebook still feels plenty warm (GPU being worked?), so the fans stay ramped up most of the time (even with the CPUs not being hot at all).

    The original MacBook fans used to closey follow the CPU temp. The CPU would get hot briefly, so the fans would spin up and then spin back down. When it did that, people on the forums complained that the MacBook fans "mooed".

    The original MacBook and MacBook Pro fans were adjusted a few times via firmware updates. I'd be surprised if the same thing didn't happen for the Air.
  13. MarkF44 macrumors member

    Apr 6, 2008
    Hi !

    I own the MBA since a week only so I can't tell if there is more 6200 RPM with ot without the battery plugged.
    However, that's true that the bottom can run hot, I wonder if the fans is efficient, I can't find in the footprint which ones are to get the air into our out of the case.
    Yes there is no room in the mba but the air flow circuit seems odd to me...
    I've read on this thread that peoples that have no USB devices connected also experience the 6200RPM "issue" as well.
    I have the ethernet USB adapter connected and both airport and bluetooth deactivated, it doesn't explain that fans run crazy because if I just use mail, the computer can run 3 hours at 2500RPM and I am a bit disappointed...3 hours only !
    I am doing the battery calibration...
  14. Thomi macrumors member

    Jan 30, 2008
    Well, I think that we first have to cycle down the battery a few times before it gets the full capacity. Concerning the fan I would like to clarify for those who are reading these articles without having bought their own MBA yet: This machine is the most silent one I ever owned, by far!! Even the HD version doesn’t produce ANY noticeable sound to me as long as there is no heavy cpu load. It seams that there is room for improvement on the higher edge of use, which might be addressed soon. But nevertheless: for my daily work this thing is marvellous. I'm loving it. :p
  15. rom macrumors regular

    Jun 7, 2006
    Ethernet via the USB dongle eats up CPU resources because processing of the packets is done in memory rather than by the separate chip. The more stress you put on the CPU, the hotter it gets.

    BTW, you may need to calibrate the battery again. Did this and at 2500rpm, I can get up to 4.5 hours.
  16. MarkF44 macrumors member

    Apr 6, 2008
    ethernet adapter sucks, I don't think it uses a lot of CPU, however it uses a lot of battery life, almost 50% more battery life without adapter (4H30 vs 3H) airport seems better (3H30 with vs 3H without airport)

    the fans seems to run crazy when the bottom gets hot, e.g. very often. the footprints are not at the good place, if I use the laptop on my knees or in the bed I have to care about the footprint freespace, even if I do the bottom get hot but it is quite easy to forget that footprints don't see fresh air anymore...

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