Weird 3-5 minute heat-related slowdown on Macbook?

Discussion in 'Mac Pro' started by mattpeckham, Jul 4, 2006.

  1. mattpeckham macrumors newbie

    Jul 4, 2006
    Anyone seen this? Whenever my brand new white Macbook 2.0 GHz w/1 GB RAM (4H626) passes ~65C, everything goes super-jerky, meaning that Expose, Dashboard, the Dock, etc. all turn into a slideshow and stutter horribly. As long as the temp sits in the 65C+ range, it remains stuttering.

    I was testing using 'yes > /dev/null' and even if I kill Terminal entirely, it won't start responding normally (quickly) again until the temp bumps back down to around 60C or below. I can reproduce this error every time I push the temp over 65C. My ambient temp is 70F and the Macbook just feels a little warm when it's cranking in the 70C range, so I'm at a total loss. Defective? I've tried replacing the factory 256/256 RAM and it made no difference. Reboots make no difference. And yes, I've scoured the process manager...when the jerking/stuttering is occurring, the CPU is about 2-3% busy (the busiest process is the utility window, in fact, so it's not an app or process hanging me up).

    Initially I thought it might be something I'd installed in the process of updating to 10.4.7, so I rebuilt the Macbook from scratch, clean install, minimal bundled apps. I know it's not the apps or my config, because the problem kicked in immediately, as soon as the 3D "spinning" registration cube came up (where you select English, then input your name, etc.). It continued jerking all the way through to loading the desktop. I rebooted, and as it came back up, still jerking (the temp was pretty high from all the DVD spinning and CPU-related file copying during soon as the temp dropped a bit, bingo, it was smooth again).

    I'm planning to take it in to the Apple Store tomorrow (I bought it a day ago) and show them, then illustrate it *not* happening on any of their demo Macbooks for comparison, before I just swap it out for a new one.

    Anyone else seen this?

  2. FullmetalZ26 macrumors regular

    Jun 12, 2006
    Sounds like maybe the heatsink isn't making good enough contact with the CPU/GPU dies, which subsequently overheat, and the heatpipe-mounted thermal sensor report the wrong values. Video chipsets seem to be particularly sensitive to overheating, which would explain the jerky video. Makes me wonder how that could possibly end up happening, though...
  3. mattpeckham thread starter macrumors newbie

    Jul 4, 2006
    Yeah man, I'm stumped. Other than that one thing, the Macbook runs like a champ. Not a single thing else to complain about. Heck, even totally pegged and dragging windows around to slam the CPU, the hottest it gets is around 75C. Compared to the horror stories I've heard about 90-100C temps in earlier revs, I feel blessed.

    I was all set to get down to business when this issue reared its head. Oh, and I ran hardware diags, and everything checks out AOK (though of course heat-related issues don't show up as errors).

    And the CPU frequency *technically* shows 2.0 GHz in Hardware Monitor, so I know the cores aren't throttling back. It almost has to be something to do with the video card, but sadly I'm at a complete technical loss as to what about heat would cause a video card of all things to blow its cookies. Video cards (in my experience) are typically spec'd with much broader thermal ranges than CPUs.
  4. FullmetalZ26 macrumors regular

    Jun 12, 2006
  5. purelithium macrumors 6502


    May 28, 2006
    Kingston, Canada
    Honestly I've never had that problem, I'd call Apple, or take it in to get looked at. That's a pretty crazy bug.
  6. dclee9 macrumors newbie

    Jan 8, 2008
    I also experienced the same problem.

    I can feel the hot air coming out from the screen and fan running at full speed.

    I'll see 1/2 to 1 sec delay on the little green light when I switching the "Cap Lock" and everything I run will be extremely slow.

    I have 2 gig of ram and just running Firefox and Java at the same time I know I should have plenty of memory left to run this two programs.

    I'm running Leopard, CPU 1.8 GHz core duo white.

    EDIT: i think my macbook's random slowndown is also cause by heat related. It happens when it's hot.
  7. aaronw1986 macrumors 68030

    Oct 31, 2006
  8. sebastianlewis macrumors regular

    Jan 2, 2007
    San Francisco
    Yes, but old thread. This one is from 2006. I also get heat related issues though, sometimes taking my Airport with it (Macboook late November 2006 edition, from after this thread was started), I don't really think much of it though as long as I keep the temperatures way down, but it is annoying that I have to continue to do maintenance even while working sometimes.


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