iMac Freeze Cause Determined?

Discussion in 'iMac' started by jaw1034, Apr 23, 2009.

  1. jaw1034 macrumors newbie

    Apr 17, 2009
    Anyone have a freezy iMac with less than 8GB of ram installed? I made a brief attempt to search the forums for an answer to this, but was unsuccessful.
  2. Omni Geno macrumors regular

    Omni Geno

    Apr 8, 2005
    Los Angeles, CA, USA
    I have 4GB installed. And it has frozen a few times. But only with wifi on. Sorry.
  3. jaw1034 thread starter macrumors newbie

    Apr 17, 2009
  4. Tymbo macrumors regular

    Mar 5, 2009
    It is strongly believed that if you have wifi enabled, you will experience freezes, but it your computer is wired via ethernet, you won't.

    Hope this helps.
  5. GonzoRob macrumors 6502


    Sep 1, 2004
    A few days back I ran a bunch of tests to prove this theory. Still managed to freeze the imac with wifi disabled in both osx and windows...

    I concluded it's not driver related, wifi related or (after some other tests) bluetooth related.

    I think turning off some of these can help reduce the problem - it's very confusing :confused:

    (PS: I do think this can be fixed with a firmware update, but i think it'll take apple months to do anything about it... )
  6. dolmen69 macrumors newbie

    Apr 22, 2009

    Hi GonzoRob,
    I think your tests lead definitely to a conclusion: new Imac with 4850 have a "thermal budget" problem. The more you switch on the more you heat the graphics card. Then, the more the GPU mounted on is sensibly on heating the more you 'll get a freeze.
    I am lucky that, as soon I switched off Wifi I got no more trouble. What I think is that my "Temperature bar" (getting more than this you'll freeze) is slightly higher then yours, I can heat more my GPU then you yours.

    I have a MBA that with wifi on it seems burning (metal case does not help).
    This to say that, for thermal budget, Wifi is playing a big role.

    The conclusion is the following: HOW TO FIX THIS INTEGRATION ISSUE WITH A SW FIX, APPLE ?

  7. jmpage2 macrumors 68040


    Sep 14, 2007
    It doesn't make sense that heat is the issue when people have had freezes and lockups during the opening video when the machine is first turned on.
  8. jtourville macrumors newbie

    Apr 19, 2009
    I suspect the problem may be power related. I was experiencing the same freezing problem people here are posting and with similar circumstances (doing something graphics-intensive and using wifi). But I too would see the problem way too soon after boot to think it would be heat related.

    After I sent my iMac off for replacement, though, I noticed a red light on my UPS that said "building wiring faulty". Plugged into a different outlet and the light went away. I have had a printer plugged into the "faulty" outlet for years with no issues. But I'm wondering if the iMac, needing more power than a printer, was getting inconsistent power from the outlet and failing because of that.

    Now I doubt that everyone having this problem has faulty wiring in their wall, but it's something to chew on... In any case my replacement should arrive on the 28th, so I guess I'll see if it works better on the good outlet.
  9. nss.aries macrumors member

    Feb 16, 2009
    I'm doing some tests with my iMac with airport turned off.

    I'm playing simoultaneusly 2 movies (1 HD) with Quicktime and VLC, music on iTunes with Visualizer, video playlists on youtube and I opened a big image (4000px width, 400dpi) in Corel Painter.


    6 hours has passed and no crash yet. Maybe it will crash just after this post ;) but with airport turned on it would have crashed before.

    These are the temps in this moment:


    I'll keep running those things tonight.
    Tomorrow TNT will come and get these machine, when the new one will arrive I will test it with airport turned on and if, as the lucky of mine makes me believe, it will crash again, I'll keep it wired 'till Apple fix this problem.
  10. GonzoRob macrumors 6502


    Sep 1, 2004
    With both my freezing imacs, the freezing rarely occurred when under pressure. Usually just when I'm running apps.

    Also, interesting thing; it froze on Left 4 Dead just now and the audio sounded like a fraction of a second of audio was stuck on an infinite loop.

    Can hardware cause infinite loop crashes? I thought it could only be created with duff software (including drivers and firmware)

    Perhaps I got it the wrong way round and it's *always* a hardware issue ;)
  11. Theraker007 macrumors regular

    Mar 3, 2009
    me too, of my 4 crashes so far, 3 have been while running barely anything at all.

    i also had that audio problem during a crash u described from itunes.
  12. DM82, Aug 12, 2011
    Last edited: Aug 12, 2011

    DM82 macrumors newbie

    Aug 12, 2011
    iMac freezes 1 minute after startup

    It's an old thread, but it seems to be the same problem.

    I bought my iMac (intel) somewhere in 2008. Currently running 10.5.8.
    It has been wifi connected since day one. Never any issues whatsoever.

    Last week suddenly it did not awake from sleep mode anymore.
    Upon restarting it froze after about one minute. Cursor still moved, but when I clicked something I got an infinitely spinning beach ball.

    Resetting PRAM and NVRAM did not change anything.

    A combination of things seems to work (sometimes!): in the minute time I get before it freezes, I hit alt+cmd+esc a couple times, turn off airport and wait. When it not freezes I can turn airport back on again, and, like right now, everything works fine again. Also sleep mode creates no issues.

    When I restart the same trouble starts all over. Also in save mode.

    Any ideas what might cause this? I figure this is software related somehow. I may have run an update just before all this happened... I'm not sure.
  13. cocky jeremy macrumors 68040

    cocky jeremy

    Jul 12, 2008
    Columbus, OH
    My iMac started doing it after i installed Lion. Very, very rarely would it freeze on Snow Leopard but once i got Lion, BOOM. 5 times a day or more. I installed smsFanControl (Defaults are 2200rpm now) and i rarely get freezes anymore. I went from 3-7 times per day to maybe 1-2 times per week. Hopefully a firmware update can fix it all together.

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