Berry with an "A"

Q: 27-inch / 27" iMac Random Shut down

SPECS:____________________________________________________________________________
• 27" 2.8 GHz Intel Core i7 / 8gig / 1TB
• OS 10.6.3 (about to update to 10.6.4)
• All firmware updates have been applied according to software update
• 3 external drives: 1-320 gig 800fw / 1-TB USB 2.0 / 1-500gig USB 2.0

INFORMATION:____________________________________________________________________

I've been running with this configuration ( 3 extra drives) since approximately December with no issues. Out of the blue... only running Aperture and Safari - my iMac JUST SHUTS off- WITHOUTwarning. It acted as though I was running a MacBook and the battery going dead/asleep. That's how random and sudden it shut down - NO WARNING. I did have the iMac asleep for about three hours before coming back to it to start working again when it shut down, but it should have even been cool.

I only started reading around on the web to see of other incidents after this random shut down this evening, but I can't find anything specific. I've found A LOT of similar things - all seemingly related to "HEAT."

And heat seems to be a certain issue recently - in the last day or two. Today I noticed my top back side to be hot, which isn't uncommon, however, it became so hot I really wasn't able to keep my hand on the top back. I've also noticed A LOT of spinning beach balls, and lots of processor delay! Heat??

There are NO energy saver pref's set to automatically shut it down. The power was and is firmly set. There are no network settings, nor access to the iMac to have it shut down. It is not shared with anyone on the network.

SUMMARY:___________________________________________________________________________

• Today, I grabbed a couple temp / monitor widgets and am trying to watch the data. All components seem to be at/around/below 140 degrees F with ambient air at 77 degrees. I don't know numbers, but that all seems reasonable.
• Going to update to OS 10.6.4 (doubt that's it!!)
• I'm going to run the hardware test from my disc to see if ANYTHING. 8-p
• AND... I'm going to call Apple to set up a case. It's still full under warranty, and I have 2 more years of AppleCare on it. But there's been too many things pointing to hardware to call this a software issue.

I've dodged all the display issues with my iMac, but now.. I'm a bit hacked knowing how much I spent on this thing, with the initial DELAYS I went through, ordering it before it had even been released!

?? QUESTION ??_____________________________________________________________________

So, has anyone else been having this issue, heard of a solution, seen anything on Apple's website of known issues ??

Barry
( Grumbling bout my Mac)

Which one of twelve??, Mac OS X (10.5.6), ever hear Newton?!! ;-) One of those, too!

Posted on Jun 22, 2010 8:59 PM

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Q: 27-inch / 27" iMac Random Shut down

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  • by MattOC,

    MattOC MattOC Sep 11, 2011 3:26 PM in response to Jeff.C
    Level 1 (0 points)
    Sep 11, 2011 3:26 PM in response to Jeff.C

    That's bad news  

     

    I finally replaced my Crucial ram with Samsung ram from OWC/macsales.com and have been doing great ever since - no shutdowns at all with full iPhoto usage (that I used to not be able to do)

     

    Has anyone else on this thread upgraded to 7.0 or 7.01 and re-experienced issues after previously solving them with new RAM?

  • by sixteenbits,

    sixteenbits sixteenbits Nov 7, 2011 9:40 AM in response to architextus
    Level 1 (0 points)
    Nov 7, 2011 9:40 AM in response to architextus

    This is a really interesting thread. I have a late model 2011 iMac with an i7 and 16GB of Crucial RAM. I have never had an issue with random shutdowns or black screens, thankfully, but I do have an issue where I can't install anything by disk -- https://discussions.apple.com/message/16651614

     

    I wonder if this is the same issue. I'm on 10.6.8 but am thinking of upgrading to Lion. Does anyone have new information on how their iMac is running on Lion, especially with 16GB of Crucial RAM?

     

    Crucial offered me an RMA, but I don't know if that's going to really solve the issue. All my tests (inlcuding 24hours of Memtest) came up totally spotless...

  • by teemula,

    teemula teemula Nov 9, 2011 12:37 AM in response to Berry with an "A"
    Level 1 (0 points)
    Nov 9, 2011 12:37 AM in response to Berry with an "A"

    Still having problems after upgrading to Lion. Tried with 16GB Crucial memory, had to reduce down to 12 because of the random shutdowns. Same on Snow Leopard with Kingston 16GB and Crucial 16GB. No way to reproduce the problem, it just happens.

  • by sixteenbits,

    sixteenbits sixteenbits Nov 9, 2011 12:52 AM in response to teemula
    Level 1 (0 points)
    Nov 9, 2011 12:52 AM in response to teemula

    Teemula, do you experience any issues after dropping down to 12? Or is everything fine at that point?

  • by teemula,

    teemula teemula Nov 9, 2011 1:01 AM in response to sixteenbits
    Level 1 (0 points)
    Nov 9, 2011 1:01 AM in response to sixteenbits

    Not a single problem with this issue after dropping one of the sticks out and using iMac with 12GB. Its been running just fine.

  • by andym00,

    andym00 andym00 Nov 9, 2011 1:54 AM in response to teemula
    Level 1 (0 points)
    Nov 9, 2011 1:54 AM in response to teemula

    Just to add, it's been 2.5 months since I pulled one of the 4GB sticks out of mine (reducing it to 12GB) and it's been running perfectly since then.. I did contact Corsair, but got some wishwashy response and really couldn't be bothered with the hassle, so I've used the spare stick to bolster up a laptop that only had 4GB before

  • by shadowhywind,

    shadowhywind shadowhywind Nov 9, 2011 4:03 AM in response to andym00
    Level 1 (0 points)
    Nov 9, 2011 4:03 AM in response to andym00

    For those that are still having issue, either contact the manufactur of the ram and request/demand a replacement or a refund of what you paid. So far from the sounds of it, Samsung and Mushkin have solved there issues. I have been running 16 GB, running Dreamweaver, photoshop, xcode, aperture + 10 other programs at the same time, with at least 16 days of uptime without a shutdown. So, since you paid for an imac that supports 16 gb, and paid for 16 gb, don't settle for 12.

  • by rseijas,

    rseijas rseijas Nov 9, 2011 4:32 AM in response to shadowhywind
    Level 2 (168 points)
    Mac OS X
    Nov 9, 2011 4:32 AM in response to shadowhywind

    I too have been running with 12GB only after the full 16GB (Crucial RAM) caused the random shutdown issue for me. I pulled two of the 4GB modules and put two of the original 2GB modules back in. I'm running 2x4GB and 2x2GB, and I haven't had a single shutdown ever since doing so. I don't notice any performance difference between my current 12GB configuration vs. 16GB.

  • by Alien Quattro,

    Alien Quattro Alien Quattro Dec 1, 2011 9:18 AM in response to orbeck68
    Level 1 (0 points)
    Dec 1, 2011 9:18 AM in response to orbeck68

    Just to shoot you guys and update in terms of what worked for me:

     

    Yes the problem is due to using 16GB of RAM. This problem does not seem to occur when using 12 GB of RAM.

     

    I've conducted these tests using Premire. With 16GB crash after the computer reaches a certain temperature (apx. 120-130C), the computer will shut down. With 12 GB the temperatures seem to not trigger the issue below.

     

    These 27" imacs suffer from this issue:

     

    It turns out that Mac Intel chips have a built-in feature called THERMTRIP that will temporarily suspend the CPU when things get hot, and shut down the CPU altogether when things get too hot. Speculation is that this temperature is somewhere in the neighborhood of 120-130ºC.

     

    One way to workaround this issue is to use the smcFanControl app. I use it and have configured a setting that boosts the ODD and CPU fan speeds to keep the temperature below 120-130C. This seems to be working well.

     

    You can use iStat Pro to monitor your temp. However, the smcFanControl app also monitors your temp.

     

    I strongly feel that Apple should do something regarding this issue. If you use Applecare, they'll just say that they can't find anything wrong, or will replace the MB only to have the problem reoccur. They may also suggest purchasing new RAM, which many have done with no luck.

     

    Hope this helps. Please reply if you are able to get a realistic resolution from Apple.

  • by Alien Quattro,

    Alien Quattro Alien Quattro Dec 1, 2011 9:21 AM in response to shadowhywind
    Level 1 (0 points)
    Dec 1, 2011 9:21 AM in response to shadowhywind

    shadowhywind wrote:

     

    For those that are still having issue, either contact the manufactur of the ram and request/demand a replacement or a refund of what you paid. So far from the sounds of it, Samsung and Mushkin have solved there issues. I have been running 16 GB, running Dreamweaver, photoshop, xcode, aperture + 10 other programs at the same time, with at least 16 days of uptime without a shutdown. So, since you paid for an imac that supports 16 gb, and paid for 16 gb, don't settle for 12.

     

    Are you running these on Lion? How has it performed since your last post? what are your temps when using these apps?

  • by Alien Quattro,

    Alien Quattro Alien Quattro Dec 1, 2011 9:24 AM in response to teemula
    Level 1 (0 points)
    Dec 1, 2011 9:24 AM in response to teemula

    teemula wrote:

     

    Still having problems after upgrading to Lion. Tried with 16GB Crucial memory, had to reduce down to 12 because of the random shutdowns. Same on Snow Leopard with Kingston 16GB and Crucial 16GB. No way to reproduce the problem, it just happens.

     

    See my quote below regarding temperatures. Lion also, seems to increase CPU temps across the board.

     

    It turns out that Mac Intel chips have a built-in feature called THERMTRIP that will temporarily suspend the CPU when things get hot, and shut down the CPU altogether when things get too hot. Speculation is that this temperature is somewhere in the neighborhood of 120-130ºC.
  • by teemula,

    teemula teemula Dec 1, 2011 9:47 AM in response to Alien Quattro
    Level 1 (0 points)
    Dec 1, 2011 9:47 AM in response to Alien Quattro

    Problem SOLVED!

     

    I got new memory from Kingston and it fixed everything. No problems after two weeks of regular (and sometimes heavy) use. Photoshop, Final Cut Pro, Illustrator, InDesign running almost full time with some standard apps and no problems at all, not a single shutdown.

     

    I haven`t done anything else to my iMac, just replaced 12GB of Crucial to 16GB of new Kingston Ram. No major updates on Lion, no extra installs, nothing.

     

    Whole thing started in november 2010 when I bought my iMac with 16GB Kingston memory. System started crashing in first week, I took 4GB out and it was fine. Received 16GB of new Kingston memory, problem persisted. Changed to 16GB Crucial memory, problem persisted. I was in the middle of a big project and had to get stable system so I took 4GB off and everything was fine. Two weeks ago I received 4x4GB of new Kingston RAM and this fixed my problems. Now running 16GB and everything is rock solid as it was supposed to be in the first place.

  • by Gandalf The Grey,

    Gandalf The Grey Gandalf The Grey Dec 7, 2011 6:06 AM in response to teemula
    Level 2 (275 points)
    Dec 7, 2011 6:06 AM in response to teemula

    teemula,

     

     

    The odd thing for me, my computer ran fine for the first 6 months and now I have random Kernal shut downs, they ran a system hardware check and my SSD Drive was corrupt. They replaced the drive everything seemed fine for a week or so and then it started happening all over again. First Mac in 8 years with any problems, but this problem is driving me nuts! I have 3 years of Apple care, I wouldn't have an issue with taking it in again but, hauling a iMac into the store is a pain in the ***!

     

    My system is a iMac 27" i7 with 16gig of Apple memory with SSD drive and 2TB hard drive.

    Using 10.6.8

     

    I have done all the reseting of everything several times over a replacement drive etc.. Open to any suggestions

    as last night while runing Preview looking at several pictures, it crashed about 5 times.

     

    Thanks for any help!

  • by Alien Quattro,

    Alien Quattro Alien Quattro Dec 8, 2011 9:23 AM in response to Gandalf The Grey
    Level 1 (0 points)
    Dec 8, 2011 9:23 AM in response to Gandalf The Grey

    Gandalf The Grey wrote:

     

    teemula,

     

     

    The odd thing for me, my computer ran fine for the first 6 months and now I have random Kernal shut downs, they ran a system hardware check and my SSD Drive was corrupt. They replaced the drive everything seemed fine for a week or so and then it started happening all over again. First Mac in 8 years with any problems, but this problem is driving me nuts! I have 3 years of Apple care, I wouldn't have an issue with taking it in again but, hauling a iMac into the store is a pain in the ***!

     

    My system is a iMac 27" i7 with 16gig of Apple memory with SSD drive and 2TB hard drive.

    Using 10.6.8

     

    I have done all the reseting of everything several times over a replacement drive etc.. Open to any suggestions

    as last night while runing Preview looking at several pictures, it crashed about 5 times.

     

    Thanks for any help!

     

    I would probably try to do a fresh install of the OS, or upgrade to Lion since you are experiencing kernal errors. Have you zapped the PRAM? Try downgrading to 12GB of RAM to see if that resolves the problem also.

  • by jrey1234,

    jrey1234 jrey1234 Dec 28, 2011 6:12 AM in response to Alien Quattro
    Level 1 (10 points)
    Dec 28, 2011 6:12 AM in response to Alien Quattro

    So this seems to have resolved the issue for me as well.

     

    My system (27" Mid 2010) never really shutdown or panic. I would just get GPU dropping into Debug mode in the log. after which the Mouse and Keyboard would stop responding and I would have to ssh in and run shutdown or power the unit off.

     

    I had tried smcFanControl with no luck in stopping the issue, although it did run cooler..

     

    The part I don't really understand is the 16GB lets call them 8GBA and 8GBB when all installed causes the issue. When running 12GB with 4GB and 8GBA  it works fine, or when running 4GB with the second set 8GBB it works fine.   To me this implies that there is really no problem with either of these sets of memory. 

     

    Implies to me either to be a problem with LION and 16GB on this mother board combination or ?

     

    either way 12GB configuration works.. go figure.

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