Mid 2007 Macbook Fan Problem

Discussion in 'MacBook' started by Mewsic, Sep 30, 2010.

  1. Mewsic macrumors newbie

    Sep 30, 2010
    Hello all,

    Specs of the offender!

    Mid 2007 Macbook
    2.0 ghz Intel C2D
    Mac OS X 10.6.4
    2gb 667 DDR2 SDRAM (recent upgrade)
    40 gb Solid State Hard Drive (recent upgrade)

    This is my backup computer that I use infrequently. About two weeks ago I noticed that the fan was screaming and running at a ridiculously high speed (over 6200 rpm's) only when I was watching video on justin.tv. Through reading and researching I tried a few different things.

    1. smcfancontrol - no luck
    2. smc reset - no luck
    3. PRam Reset - no luck
    4. Bought a can of compressed air and cleaned external venting. no luck
    5. Replaced internal fan and cleaned enclosure with compressed air. no luck
    6. Tried some of the more common things I found on the interwebs. Watching the activity monitor for anything erroneous (the only thing I notice is that the browser in use seems to be the problem), checking to see if a print job was in cue (there was none, a printer isn't even listed) no luck

    Here is what I have noticed. It ONLY starts flying when I am watching video on the screen (justin.tv as an example) When I minimize the screen or open up another tab in the same browser, the computer seems to slow down to a normal speed (between 1700 and 3000 rpm's). I tested this in 3 different browsers with the same result (Chrome, Safari, and Firefox).

    My next step was to do the Apple Hardware Test and guess what? My superdrive is bad...Boo

    Is there a way to run the AHT without a cd?

    What am I missing here? Is this a software error?

    Is it a temperature sensor? Can I replace them myself? Should I go straight to replacing the logic board?

    I realize I am a noob to macrumors, but this computer was my late younger brothers and I am determined to keep this computer running for as long as Apple has parts floating around. This isn't just a backup computer to me, this is a piece of my brothers history.

    Thanks for all of your suggestions/help in advance!
  2. Pax macrumors 6502a

    Dec 12, 2003
    You need to look at your CPU load when the problem occurs
    [I am surprised spinnerlys hasn't been on here yet to show you how ;)]
    That way you can tell whether it's a problem caused by software, or by a fault with the hardware.

    When the fans are running hard, open Activity Monitor, select All Processes, and click to sort by CPU load.

    You can post your results on here by taking a screenshot, or just paste the text to show us which processes are using the most CPU and how much. Eg Flash player 75%, Safari 25%, whatever

    Then we can diagnose & suggest.
  3. Mewsic thread starter macrumors newbie

    Sep 30, 2010
    Hi Pax: I tried getting istat in the photo too out of the dashboard. Thats why the photo is so dark. What do you think?

    Attached Files:

  4. trayanscragg macrumors regular


    Jun 9, 2010
    Judging from the screenshot you posted i think that you may be viewing a flash related website in chrome hense it is using so much out of your CPU to render the graphics? Try quitting Chrome and using another browser?
  5. Mewsic thread starter macrumors newbie

    Sep 30, 2010
    Hi Tray:

    I tested this in 3 different browsers with the same result (Chrome, Safari, and Firefox).

    I really think that Flash is the culprit here, but what triggered it? Am I missing a plug-in?

    Their has to be a cure!
  6. Pax macrumors 6502a

    Dec 12, 2003
    Nice work, that image is perfect

    As trayanscragg says, your hardware looks in good shape (CPU, thermal paste, fan all look good)

    The problem is Flash. Flash on the Mac is a beast, it uses loads of CPU. In older Macs like yours, the fans zoom up to full speed at the slightest excuse.

    My 2006 Macbook is exactly the same. The newer Macs are much, much better for this

    You have a couple of options
    - try the latest version of Flash, codename Gala, version 10.1, from Adobe*
    - live with the noise
    - buy a new Mac :)
    - install a flash blocker for your chosen browser to prevent Flash playing unless you click on the banner

    * Flash 10.1 has some optimisations in it, IIRC it uses much less CPU than earlier versions. It also offloads some of the work onto the GPU, but that depends on what GPU you have and what content you are looking at. Take a look on the Adobe site and use Google. I can't remember all the details.

    PS if you do this and it helps, come back on here and post another screenshot with Flash 10.1 running the same movie, I would be v interested to know the results.
  7. Mewsic thread starter macrumors newbie

    Sep 30, 2010
    I have the most current version of Flash ( in all of my browsers. I thought that offloading was only on the new "i" chipsets. Maybe I'm not remembering correctly.

    Regardless, I dl'd a fresh copy of flash ( in firefox and in under 3 minutes the fan was back to 6200 rpm's. This was the same test as before: A Justin.tv channel running NBC's "the office" on loop.

    What I'm trying to figure out is why the fan only freaks out if the video is visible on the screen. If I open another tab in the same browser, place activity monitor in front of the video, or open up another browser and place it in front of the video, so the video is in the background running but not viewable; the fan slows down gracefully to a respectable 3000 to 4000 rpm's, sometimes even lower!

    Where do I go from here?
  8. Pax macrumors 6502a

    Dec 12, 2003
    Hmmm, short of buying a new Mac I can think of some things. Some are a bit flakey and technical.

    1) Google versions of Gala and CPU/GPU combos

    My memory of this is a bit vague, but IIRC there was a beta of Gala which had GPU acceleration, but the release version did not. Or something. And Gala definitely works on Core2Duo Macs. It depends on the GPU, not the CPU. IIRC the 9400M and the GMA950 work. Also it only accelerates some content (H.264?). But worth checking this out properly.

    2) Change the fan control algorithm to trade off fan speed for CPU temperature

    The stock fan control algorithm on older Macs is very aggressive. As soon as the CPU gets warm it really winds up the fans. Your CPU is only at 66 C (sorry I'm metric). Your C2D has a specification limit of at least 95 C (possibly 105 C but I think not). The fan doesn't really need to be at 6200 rpm. You could download a new fan control algorithm, there is one called Fan Control, and use it to trade off a bit of CPU temperature for fan speed. I doubt you would need to take the CPU to anywhere near its spec limits. For example I bet that allowing the CPU to get to 80 C when viewing the same movie you would reduce the fans to perhaps <5000 rpm. Which might make a big difference to noise. Some people are a bit leery of letting their CPU get that hot. Personally it doesn't bother me, I trust Intel to make good chips.

    3) Undervolt your CPU to reduce heat output

    You could try Coolbook and undervolt your CPU. Even a small change in CPU voltage might make a big difference to the heat output of the CPU.

    (2) in combination with (3) could be a really good fix. But as I said they're both quite technical solutions and do involve messing with your Mac's firmware - always a slightly concern.

    If any of this works out, I'd love to hear about it. Best of luck

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