Core Shutdown Solutions

Discussion in 'MacBook Air' started by ercanbas, Aug 8, 2008.

  1. ercanbas macrumors regular

    Feb 15, 2008
    So I want to get everyones opinion. I am not as tech savvy as I would like to be and the MBA HD is my first Mac purchase computer-wise (proud owner of first gen Iphone and iPod nano). I was curious if any of you think that core shutdowns can be resolved via software update. Updates in the past seemed to fix some problems. Like myself, many of you resorted to coolbook which is great but sometimes I ponder why my hard drive is at 6200rpms meanwhile the only thing that is running is Safari. Please chime in with your opinions and perhaps some better coolbook settings (lol).

    PS I am using the settings from the "huge success undervolting thread"
  2. shrtmkr macrumors regular

    Mar 10, 2008
    the apple
    I think it's possible.If we assume it gets core shutdown, when the graphics card deal with java apps.
  3. kingcrowing macrumors 6502a


    May 24, 2004
    Burlington, VT
    Mines never had a core shut down even when doing a video encode for over an hour or hour plus video chats. It will get hot (80 is the highest I've seen it) but only after doing a lot for a long time but its right now 41 on my lap with iChat and safari going.
  4. shrtmkr macrumors regular

    Mar 10, 2008
    the apple
    what week was it build on? according to the serial on the bottom.

    00 will represent the week
  5. gcmexico macrumors 6502a


    Dec 22, 2007
    New York City
    wow that's matter what I'm doing, I'm usually breaking 50, anything involving video, I'm passing 60
  6. Olvenskol macrumors member

    Feb 20, 2008
    I'd be surprised if a software update could do anything other than what Coolbook is doing.

    Core shutdowns come from the CPU overheating. The CPU has two processing cores. If things get too hot, it shuts one of them down to let things cool off a bit. The alternative is letting the heat rise to the point where something breaks, so this is actually a cool feature ;-)

    To avoid a core shutdown, you fundamentally have to either generate less heat or dissipate the heat faster. Coolbook lets you generate less heat by supplying less current to the CPU. You can take this down as far as you like until the CPU simply stops working. The precise point this occurs is different for every individual chip. What Intel does is publish a spec that gives them generous wiggle room to insure there is enough current to run the chip. Apple simply implemented that spec. What Coolbook does is let you play in the wiggle room.

    Alternatively, you can just slow the CPU down. This also lets you provide less power to it, but more reliably. I think you can probably do this via Coolbook too (by eliminating the 1.6 GHz entries), but I'm not certain about that and haven't tried it myself.

    On the heat dispersion side, all you can do is open up the machine and play with the heat sink. The people that reapply the heat sink paste are trying to get better heat dispersion. Some are apparently successful! I haven't tried it myself, since Coolbook has done great for me.

    For some people, the fan controller seems kind of wonky, running the fans too high for too long. That probably is fixable via software. But that is a noise issue and not a core shutdown issue.

    My own feelings about the heat issues with the machine are that I think the design is adequate, but only barely so and manufacturing errors easily let it get into the not-so-good range.
  7. hkq37 macrumors newbie


    Apr 26, 2008
    Hong Kong

    Possibly, but I disagree. I think there is quite a bit of speculation about whether software updates since the MBA release has stopped cores shutting down. Some people say yes , some say no. Most people who are interested in this issue go the re-application of heatsink paste+Coolbook route and viola! problem solved.

    But one thing has been determined previously and that is that heat is NOT the factor which determines whether the cores shutdown. It has been discussed in some older threads (i.e. 'Be gone! noisy Macbook Air') or for further proof you can look at this old screen capture of mine.
    (showing core shutdowns at low temps- 65C). Core shut downs are a feature of the chip, however, this has been poorly implemented under native software and the fact that the factory cakes thermal paste in an inefficient manner does not help either.
    Since I went the re-application of AS-5 + Coolbook, I cannot say whether software updates have improved CPU functions. But I have noticed a lot of improvement in battery life and lower temperatures.
    For example I am using this computer on my bed now ( vents are covered over), 2500RPM, 50C about 4 hours battery expected. No problems. This is an older MBA (a week 9 manufacture) it's had 109 battery cycles.

    Original Poster:

    Also your post doesn't make much sense the HDD is only a 4200 rpm, it's either stopped or going 4200 rpm, there is no other option - assuming of course you have the HD MBA and not the SSD ,right !! :/
    I think you are getting your CPU cooling fan confused with your HDD spin rate.
    But in answer to your original question. I think yes , the CPU core shutdowns can be fixed via software. I think you can buy an MBA with confidence.
  8. ayeying macrumors 601


    Dec 5, 2007
    Yay Area, CA
    To do the reapply of thermal paste, I hope most users who attempt this route or think about attempting this route to make sure you don't bend and whatnot the heatsink. The heatsink is very fragile since it is a very thin layer of aluminum. Any bent/warp could drastically effect the cooling. I know, I bent my heatsink near the CPU contact and made CPU cooling extremely inefficient. I've ordered a new heatsink from ifixit and installed the new heatsink w/ AS5, much better cooling and no more 105 deg C CPUs.
  9. Kittychan macrumors regular

    Feb 13, 2008
    Wellington, New Zealand
    Very interesting, how do you notice the heatsink being @#$@#$ up ??
  10. andersbs macrumors newbie

    Aug 15, 2008
    Changed fan and heatsink

    I had my MBA in for service because the fan started to make a loud noise whenever the fan exceeded 1000 rpm. Apple changed the heatsink and the fan, and that seemed to solve all core shutdown problems I had
  11. ayeying macrumors 601


    Dec 5, 2007
    Yay Area, CA
    Our heatsink have barely any clearence between the actual heatsink and the bottom of the case. My heatsink was bent so there was a slight rise in which the airflow that travels along the top of the heatsink was restricted.

    Furthermore, our heatsinks aren't a single piece of aluminum. The outer layer, the black part of what you see is aluminum plating, very thin. Afterwards, there is another layer, slightly powdery/paste like substance except it is harden, could be thermal paste, then the last layer, a thin sheet of aluminum that comes in contact with the diode.

    It comes out to something like this:

    Bottom of the laptop case --

    AIR FLOW >>
    Black Heatsink Outer Layer -----
    (Thermal paste layer)
    Contact Layer ------

    AS5 or Apple Thermal Paste or whatnot
    CPU ==

    Since I had a 2nd heatsink that I didn't much need, decided to do some experiments on it. The "Thermal paste layer" between the two aluminum pieces took me near an hour to get off.
  12. shrtmkr macrumors regular

    Mar 10, 2008
    the apple
    that sounds good.
    Can you do video conference/youtube without hicks?

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