Q: OSX Lion + 2011 iMac 27'' + Video = Freeze

I was told by Apple store that I needed a new logic board. I was told by an Apple authorised repair that I needed  a new screen and another Apple authorised dealer said I needed a graphics card and another an inverter. I'm out of warranty.

I installed smcFanControl and have not had a crash in weeks.

The logic board replacement is a lazy and expensive fix. I dont think it will fix it. It's more likely GPU overheating.

Thats the point on the back of my machine that the heat was most.

I'm sorry to throw a wrench in the array of diagnostics that have taken place, but since disabling my WiFi adapter (formerly AirPort), I have not had one freeze at the login screen or during fast user switching. I don't know exactly what the correlation, if any, there is, and I'd be curious to see if this does anything for anybody else.

I am by no means claiming a solution here, because it's the furthest thing from one. I would like to know if anybody else, by disabling WiFi and using ethernet, continue to experience the sbbod or freezing.

Model Name:          iMac

  Model Identifier:          iMac12,2

  Processor Name:          Intel Core i7

  Processor Speed:          3.4 GHz

  Memory:          12 GB

I use an ethernet cable exclusively.  My WiFi isn't even on on my iMac.

Hello

I had a problem all time. Video on youtube, a little bit more work for computer, or more programs running. It crashed every time. And once it crashed, after a reboot, it took me no more than a minute, to crash it again. Took it for a repair at warranty, first they changed one memory module, and said that all is fine now. Took it home, but all was the same. Took it back to warranty next day, then they changed a GPU (that sounded much reasonable to me), and now, for two weeks, there has been no crash. Mine is mid 2011 iMac, came with lion, so i have never had a oprtuniti to trie it with leopard or snow leopard.

Best

Hi Crapplestout I so gonna try this... I assume you had been doing the "repair permissions" that the geniuos guys usually sugest to do to "improve" the performance of the system... anyways...
My model: iMac 27" 2011
2.7 GHz Intel Core i5
RAM 12 GB

Let's see if I see any improvements about this.. something that I noticed it has helping out to reduce the crashes is by not letting the system to go to sleep mode by itself but instead I put it myself if im gonna stop using the iMac (like at nite and so)... oh well That's for the post!

I've had the same problem since Nov. when we bought this piece of work.  Called applecare about 5 times, real nice, real responsive, but still no solution.

It's going to have to take something like that to get those folks off center to realize it's a real problem and bad for customer satisfaction.  Consumer reports, give me a call!

What is a "kernel_task" in the Activity Monitor?

 

I was advised by the Genius Bar to keeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeei

Can anyone tell me what the "kernel_task" in Activity Monitor is?

I was advised by the Genius Bar to keep that open and watch the grid at the bottom.  Whenever I have these "flare ups", as I just did a few moments ago where my mouse froze whenever I dragged it over Firefox, or a key stuck and repeated a letter ad infinitum, THAT is was suddenly spiked in the Activity Monitor.  With the key sticking it went as high as 90% of CUP usage.

Oh BTW - the above quote is an example of what happens when the system freezes and sticks in the middle of doing something.

http://reviews.cnet.com/8301-13727_7-20091848-263/kernel-task-taking-up-ram-in-o s-x/

You can check out this link

Hi there I tried tturning off the WiFi and only use Ethernet connection but with no difference... I still get the ramdom freezing problem... sigh.

I don't run WiFi at all and I still get the problem.

The second thing you can do is quit programs and system services that use kernel extensions, such as the aforementioned Photo Booth, or graphics processing programs and games, especially if you are running with the integrated graphics card.

That's probably why the freeze is happening mostly with video or animation.  Also why it was a MAJOR issue when going into Time Machine- both the running of an external piece of hardware AND the animation that goes on in there.  What a disaster!

I'm running 4GB of RAM and that's the most my system can take, so I can't upgrade.

I was having the same problems, took my iMac to the Apple Store on Tuesday.  They replaced the display and video card, picked it up last night (Friday) and this morning the same problem is repeating itself.  Back to the Apple Store it goes, I can't imagine what's next?

Correction, I just looked at the repair ticket and only the video card was replaced, but the problem still persist.

Just spoke with my local Apple store and am bringing it back in for repair on Tuesday.  They will test to see if the display or logic board might be the culprit and will have the parts available as needed.  Will update on the status after the repair is completed.

I decided to make a video of the issue, as I mentioned previously.  Looks like I picked just the right time.  Check it out.

http://youtu.be/EnLwJUeB6cA

PS I think this should be fine, but if anyone happens to notice anything that would be private that I shouldn't have posted publicly please let me know so I can take it down or edit it out?

Thanks!