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  • robertleeking Level 1 Level 1 (40 points)
    Bill and others,

    First of all, the mouse cursor is not created by the GPU, this is a system level device, not a graphics subsystem device. While it's true that the GPU does the work of displaying the cursor image, the OS handles updating it's position on the screen, the GPU simply draws it based on the instructions the OS passes to it.

    So, if your mouse cursor still moves the GPU isn't likely the cause. More likely, another process has crashed. Some external peripheral, hard drive fault, finder crashed etc.

    More likely, this is a software issue than hardware. I say that because you said you can access shared media remotely on the hung/crashed machine when you cannot access it on the machine itself. Bring the system up in safe mode and see if the problem continues. If it does, it's probably hardware related though it could still be a kernel level software issue. If it doesn't, it's almost certainly a software issue.
  • youngman Level 1 Level 1 (100 points)
    great, another post by someone who thinks he knows what the problem is by reading just the last page of this thread. it's already been covered that this is not a software issue. if it's a driver issue, it would've been fixed by now. if it's a os issue, it would've been fixed by now.

    this is a hardware problem affecting 2006 imacs. it occurs in tiger or leopard or snow leopard. it occurs with ATI or Nvidia cards.
  • Bill Gross Level 1 Level 1 (5 points)
    Thanks for the input. I don't know exactly how the graphics system is put together, so any insights on why these symptoms would occur is very helpful.

    The thing that made me confident it was caused by hardware was that it still happens when I boot off the DVD (and then play around in the setup program).

    Does anyone have any input from a completely locked-up system? As in, is anybody's computer so far gone that it is unusable in the GUI? Does SSH still work then, or is it just in the early stages that the whole system doesn't crash?
  • MarekSz Level 1 Level 1 (0 points)
    Hi Bill,
    if you want recover system just put it to sleep: push once power button and wait until it goes to sleep. Then wake system up and log in. Sometimes it is required to make it several times. Sometimes it does not work.
    IMHO corrupted process is Window Manager.
  • Bill Gross Level 1 Level 1 (5 points)
    I agree that it seems to be caused by the hardware. Although, since it doesn't lock up the entire system, maybe there could be a software fix.

    This, of course, is only a patch of the original problem. This doesn't speak to the argument that Apple should really be fixing the original hardware problem... but I'd just be happy if my computer stopped crashing.
  • Micah D. Level 1 Level 1 (15 points)
    MarekSz wrote:
    Hi Bill,
    if you want recover system just put it to sleep: push once power button and wait until it goes to sleep.


    Nope. Putting the system to sleep does absolutely nothing of any use, at least not for me. It just wakes back up still frozen and useless.
  • Micah D. Level 1 Level 1 (15 points)
    robertleeking wrote:
    Bill and others,
    More likely, this is a software issue than hardware.


    This absolutely is NOT a software issue. This problem occurs across multiple OS's and multiple computers. Reinstalling the entire system from scratch does nothing to fix the problem.

    Plus, during the brief few days I had a replacement vid card in my iMac everything worked perfectly fine. That card was faulty and is being replaced. Currently, with the original vid card in my iMac and quartz extreme enabled I can't do ANYTHING involving heavy graphics. With quartz extreme disabled I can do SOME things with heavy graphics, others simply cause the system to freeze.

    Again, when I had the replacement card in my computer this was NOT the situation, I could watch multiple videos and stream google earth all at the same time with no problems.

    This is a hardware issue, it is not a software issue in any way.
  • MarekSz Level 1 Level 1 (0 points)
    Well... it works for me. Give Bill a chance to try.
  • Bill Gross Level 1 Level 1 (5 points)
    Since the problem also seems obviously correlated with heat – could it be that you need to let it cool down before you try to wake it?

    I'll try it next time it freezes and see what happens.
  • robertleeking Level 1 Level 1 (40 points)
    youngman,

    I didn't just read the last few posts, I responded to a specific post because his issue does not appear to be a video card issue at all. The system is in fact NOT frozen as he can access it's shares across the network. A frozen system would not allow this.

    Also, note I didn't say this absolutely isn't a hardware issue only that it likely wasn't one. Many software incompatabilities can cause this exact issue to occurr. It could in fact be something as simple as a preferences file.
  • robertleeking Level 1 Level 1 (40 points)
    Micah,

    I'm a bit confused here. You took the video card from your iMac and placed it in other systems and it failed there also. If so, what was the point of posting in the first place, you already solved your particular issue with that single action.

    Bob and several others may not be experiencing the same thing as you and as such, in their cases it may not be a hardware issue at all. Rule out software first, then move on to hardware.

    In Bob's case, the system is NOT freezing, the UI is. This might be hardware but it also may be software, drivers, incompatable third party software and so on.
  • youngman Level 1 Level 1 (100 points)
    we already know what the problem is. it's been identified weeks/months ago. it's a defect with the gpu (either on the video card or logic board depending on the system). the symptoms appear after a year because that's when the defective component starts breaking down, usually due to heat.

    what we're trying to accomplish now is getting apple to admit there is a defect because the problem appears to be prevalent with the 2006 imacs.

    trust me, it's not something as simple as a plist or prefs file. if it were that easy or obvious, someone would've figured it out by now.

    whether one can access the imac's shares over the network or via ssh is somewhat irrelevent because the imac itself is unusable once the freeze occurs (or it shuts down, or the screen goes black while the power is still on).
  • robertleeking Level 1 Level 1 (40 points)
    youngman,

    I don't dispute that for some this may indeed be a hardware issue. I say may because Apple has a history of issuing service advisories and even offering free replacement of known problem components long after the warranty period has expired.

    Generally once an issue is known, it falls to specific serial number ranges. For example, with the Powermac G5 line, there were known power supply problems in specific production runs. Apple replaced those power supplies for quite a while after those machines were no longer under any kind of warranty.

    Getting Apple to "admit" this is a hardware problem generally requires a much larger sampling of the user community experiencing the problem. Based on the posts here, and the meager sampling found via Google searches, that sampling does not exist. This doesn't mean Apple won't do something about it only that it will take a lot more than a relative few complaints in various forums to cause Apple to act.

    Clearly, there is a problem. The question is, is it Apple's problem, the GPU maker's problem or something else.
  • Micah D. Level 1 Level 1 (15 points)
    robertleeking wrote:
    Micah,

    I'm a bit confused here. You took the video card from your iMac and placed it in other systems and it failed there also. If so, what was the point of posting in the first place, you already solved your particular issue with that single action.


    Yes, you are confused. I never put anything in "other systems". I replaced the graphics card in my iMac with a "new" one, it worked fine, but the new graphics card that i put in had a connectivity issue (nothing to do with the problems discussed here) so I have a new one coming to replace it. In the mean time I put the old graphics card BACK in my iMac and the problems immediately came back, on the FIRST boot with the old graphics card installed. That is definitively a hardware issue.


    Rule out software first, then move on to hardware.


    That's already been done. It's a hardware issue. You need to read this thread before making proclamations about things that have already been covered. It's not a software issue. It's a hardware issue.

    This might be hardware but it also may be software, drivers, incompatable third party software and so on.


    It is a hardware issue. This problem occurs on multiple OS's, across multiple platforms and regardless of third party software. It happens on machines running NO third party software, running FRESH installations of OS X, and also on machines not running OS X at all. It's a hardware issue.

    You're almost literally beating a dead horse. The software angle has been tested and that's not it. It's a hardware issue.
  • Digler Level 1 Level 1 (0 points)
    My Mac started to get lines across the screen after 1 year. Then started to freeze if closed things and open things to quickly,,, If the printer or any other drop down menu opened it froze. The mouse cursor would still move around the screen but not open anything.. spinning ball would come up. no force quit.. have to turn it off from back of screen.. I have reloaded everything disconnected everything still did not help.. But if I started it in safe boot it did not behave this way, it works.. had smc on my machine so I cranked it up way more and The lines have not appeared yet. Its been 2 days.
    My machine was purchased as a refurbished unit..
    I spent 2 months with the freezing and crap until it got unbearable and I decided it was not software.. I guess everyone should bring there computer in and refer to this forum and thread.