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Can I fix my MBA Rev A overheating issues without Coolbook?

Discussion in 'MacBook Air' started by J.C, Dec 21, 2008.

  1. J.C
    macrumors 6502


    My MBA has the usual issues with stuttering playback of Flash videos. Basically it's unusable in that respect. I've read of the success people have had using Coolbook to underclock the processor and control the fans. A colleague said I could do the same thing with SMC fan control, but it doesn't seem capable of that. If it is I'm not sure what settings to use.

    Do I need to buy Coolbook or can I tweak my MBA with SMC Fan Control or another application?

    If I definitely do need Coolbook I'll buy it, so any advice on what settings to use would be great.

    I need to cool this sucker down!!!

    Thanks :)

  2. macrumors 6502

    The theory behind using only SMC Fan Ctrl is that if the processor starts off cooler, it will take longer to heat up. This may work but you will need to set the minimum fan point to ~5,000 RPM which would be unbearably loud all the time.

    You can re-apply the thermal paste. This seems to have a significant effect on cooling.

    Outside of the two above, coolbook is really the only route.

    There are quite a few of us who have been using CB since the beginning without problems. There are 2 tricks to this:
    1. Don't just copy someone else's settings. Start conservatively and work down to find a good v to run at (mine is .9125).
    2. Always disable CB and reboot before installing OS updates.

    If you follow the two above you will be quite happy.
  3. macrumors 65816

    FYI, coolbook does NOT underclock. It undervolts. If anything, apple's solution and software update lowered the CPU speed to just 800mhz when cores got too hot.

    I used coolbook on my gen 1 and was really happy with it. It definitely made playing the computer play flash movies for hours. :p
  4. macrumors 6502a


    Nope, thats why i sold mine, I had way too many Issues with it, I really never got to enjoy it like my Rev. B.
  5. macrumors 6502a


    Well the first thing I have to say is that my MBA is the MOST temperamental computer I have ever owned (I have only ever owned macs so don't have windows comparison although I have worked extensively on them)

    I love the form factor but there are serious issues with the rev A. BEFORE I made changes then it was just a nightmare, core shutdowns and completely unusable but I did 3 things which changed it massively and made it bearable

    I first used coolbook to undervolt my Air and it was really the most beneficial thing I did. It stopped the core shut downs and lowered the temps (I have to admit I dont have exacts but I would say on average 10-15c)

    The second thing I did was write an apple script (you aren't allowed to post them in this site, search the site for tips on how to do this) that was suggested in another thread. This limited my make fan to circa 3800rpm. Above this (unless my processor has got really hot in which case I have a script to revert the fan speed) the extra RPMs were actually raising the temps by 1-2c. So for 99% of the time I have fans limited and have no issues at all and also cannot hear them :)

    Lastly I replaced the thermal paste. There are other posts about this but it was the least effective. Yes temps are slightly lower but it hasn't made a huge difference. For me, coolbook was the easiest and most effective thing to do. If you don't like it you don't have to run it but I think you would.

    So...after all of this you must be thinking that I am in love with my Air now and have it exactly where I want it, well.....no. I am SO happy to hear that the rev.B don't seem to have these issues and later on in the year I will sell this one and upgrade to the rev.B The rev.A just seemed to be too early for its time and its great to see now that all of the issues are gone in revB but I think you can get 80% of the way there and have a perfectly good computer.

    The last thing I will say is if you are not comfortable with any of the steps I have mentioned above then the rev.A is not for you. It does require care and fettling which I guess you are either happy/willing to do or are not.

    Hope this has helped PM me if you have any other questions you might not want to ask openly in the forum

    Good luck

  6. macrumors 65816

    Excellent post.

    The point with Rev A is that its up to YOU the user to make it better. Not the manufacturer. I'm still bitter about that. :confused:
  7. macrumors 6502a


    I completely agree this shouldn't be the case. I would say that I am a well informed amateur but this shouldn't need to be the case for any computer let alone a MAC!


    ps - I only bought my revA from the refurb store and wouldn't have bought it at full sticker. I got mine for £999 down from £1700. Strangely they have gone UP to £1171 now :confused::confused:
  8. macrumors 6502a

    Using a Rev B, I still have to suppress fan speed to 3600rpm. My White macbook does a far better job at fan management, idling at 1800, ramping up when needed and quickly reving back down all while controlling temps.

    It seems you've already done the care, so are you purturbed that you had to go through it or that even after all this it still isn't the machine you need? It sounds like at this point the only difference for you now is the larger SSD/HD in the Rev B?
  9. macrumors regular


    Ok, I reinstalled coolbook yesterday (10.5.6, Air Rev A, 1.6). Had it before 10.5.4 I think (removed it after Apple updated the software and "fixed" the core shutdown problem), but... since then I'v noticed (after, let's say "heavy usage" sometimes - iTunes + Flash video :) ) that kernel_task is using too much of my CPU and I don't like that. 100%-130%. So yesterday I decided to give coolbook another go.

    But I have a problem. First I'v used these settings:

    On adaptor:

    1200MHz: 0.9750V
    1400MHz: 0.9875V
    1600MHz: 0.9875V

    On battery:

    800MHz: 0.9000V
    1200MHz: 0.9750V
    1400MHz: 0.9875V
    1600MHz: 0.9875V

    Thermal limit: 85C (the max)
    Throttling level: high

    As recommended in this post. But after watching a video from YouTube, 10 mins, my Air just shut down. Just like that. Ok, processor security shutdown, I think. On the other hand, without coolbook, I would have the kernel_task at 100%, telling me "hey, you're doing too much now, I'll slow you down".

    People are saying, that I need to experiment with the settings... but is it safe ? /dev/null for 15 mins, if it shuts down, try something else, but again, is it safe ? I don't want to destroy any system files (not to mention the processor) because of this sudden shutdowns.

    And finally, I'm using lower voltage right now:

    1200MHz: 0.9000 V
    1400MHz: 0.9000 V
    1600MHz: 0.9750 V

    But what does it means ? Higher voltage = more power to the processor, higher temperature, most likely to shutdown ? So lower voltage should be allright, but will the power of the processor be good ? What do you think ? Thanks for any help...


    I'm not using SMC Fan Control. Don't mind the noise.
  10. macrumors G3


    A friend if mine had far more patience than me and she managed to get her A swapped out for a B. While still a POS, it's slightly less of a POS. She's happier now.
  11. macrumors 6502a


    Well for me the reasons for getting one were quite different to what other people may get there's for. I have a chronic problem with both my shoulders ans as such am VERY limited in the weight I can carry. So for me it was the form factor that was the most important factor. The changes I have made have meant I can use it for what I do, email and word processing really (leave the rest to my MBP), and the normal problems don't really affect it too much.
    It just seems to me like an unfinished product, rushed probably too early although I am happy with the time I have spent I will be upgrading to the Rev.B at least but I am holding out to see what Rev.C brings
  12. macrumors 6502a

    First, get rid of the thermal limit. If you don't mind the fan noise, install SMC fan control and keep it at 4000-5000 RPM, especially when plugged in. This will help in getting the temp too high. In general because of its enclosure, the MBA has a harder time reducing heat once its too hot to manage.

    Are you still getting kernel_task at 100%? It's finder related so do as much as you can to limit finder, even changing the desktop photo to a solid color helps the finder.
  13. macrumors 6502a

    Agreed, but the Rev B is a drastic architecture change which wouldn't have occurred unless Apple realized that it's early 08 path wasn't the right one.
  14. macrumors 6502a


    sometimes you pay the price of living at the bleeding edge of technology. Rev.A is (nearly) always fraught with danger. A truly groundbreaking device like this was nearly destined to have issues. I suppose the most important thing is, is that the rev.B is the drastic change we all wanted. resale prices are still good, not as strong as the MBP imho, so should lessen the blow when upgrading

  15. macrumors regular


    I switched off the thermal limit, but since yesterday (not related to the thermal limit) I can't watch full screen video for more than 40 mins or so - my Mac just switches off.

    And I don't want to install any 3rd party software for managing my fans. I think they're spinning to 6000 rpm anyway when it's too hot.
  16. macrumors 6502a

    That' called an intermission, get your popcorn refilled :D

    Are you blocking the vents during the movie? The point of SMC Fan Control is to keep the fans running as a constant rather than waiting for it to get too hot and play catch-up at 6200 rpm. Although it's a slight 2-3 degree difference, you may also want to change the thermal paste. Here's a great tut http://forums.macrumors.com/showpost.php?p=6748970&postcount=6
  17. macrumors regular


    I did, twice :D

    Well, yes with the popcorn :D. Sometimes my lid is half way open (or closed, as some people would say).

    I might try this... Did this once with my other laptop, could help... Thanks.

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