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

Hello.


Got a brand new 27'' iMac, installed Lion. The machine freezes randomly when starting to play videos, either on Youtube, Quicktime, iTunes.


When it freezes, the mouse still works, but the machine doesn't respond to any command, requiring me to hit the power button and restart the computer.


Searched on kernel.log and system.log, and found no crash/error/message.


Anyone suffering from the same problem? The machine is pretty solid, been running some OpenCL kernels too and they are ok. It's only video decoding (possible on the GPU) that seems to freeze randomly.

iMac, Mac OS X (10.7)

Posted on Jul 21, 2011 6:46 AM

Reply
2,021 replies

Dec 6, 2012 1:10 PM in response to 2rodee

No idea, the only thing I noticed that is a huge issue is the older iMacs run very hot. I was at Best Buy and Apple Store and there iMacs are left on all day long, at 5pm I was checking some out at Best Buy all of the older models were running super hot to the touch and all the newer models were almost at room tempature. Now over time the logic board, and anything else inside that iMac is going to get cooked pretty good so it doesn't suprise me Macs are failing, including my 2011 June model which I got instore credit for. Now with these new designs it seems like the heat issue which will be major factor to failure rates has been resolved. What Apple needs to do is replace failed iMac or offer some type of credit to ones that have failed over the years or less expensive replacement cost. I say go check out the new ones for yourself, even my Apple display runs hotter by itself that the new iMacs do.

Dec 6, 2012 1:20 PM in response to Gandalf The Grey

Thanks Gandalf.. I will do just that. If they hand me a box, how would I know if it was a newer model? Can I tell by the code?


I just felt the top left corner of my 2007 model (Leopard.. - but NOT for lack of trying to upgrade..) and it feels warmer than the others. I never shut it off tho. I'll do that within the next few days. I would LOVE to get rolling again.. it's been over a year of frustration. - I know you know that... I just have to vent. LOL!


Helen

Dec 6, 2012 1:30 PM in response to 2rodee

Helen,

Trying to use the Aluminum in the iMac to disapate heat just isn't cutting it with the way these iMacs run. The one I touched at Best Buy was so hot I had to remove my hand so did the Apple sales guy I was talking with. Frankly I would go into one of these stores later at night when they have been running all day long and see how hot they are, regardless what anyone tells you if some thing is that hot electronics are going to get cooked and you will end up with high failure rates that we are starting to see via the iMacs now. The newer units were not very hot at all, now I didn't get a chance to test any 27" but I will at Apple today when I stop in there store.


<Edited by Host>

Dec 6, 2012 4:44 PM in response to Om_Audio

Om_Audio: I would press them and then some. It is much easier to deal with Apple if you have a Store near by. I went in and said you can have my silver brick and give me some thing that works I started getting very loud about the problems in a civilized way and the manager said no problem here is a Apple CC card with all your money on it buy anything in the store with your credit. Now for the people that are out of Warr. a logicboard should last much longer than 4 years, if properly ventalated. I personally think these iMacs and Macbook Pros are running too hot and over time this causes the logics boards to fail sooner than later. The new iMacs I will be checking out tonight again to see if they are still putting out a lot of heat if so, I will stear clear of them and use a Mac Mini or Maybe go back to the Trusty Mac Pros


http://reviews.cnet.com/8301-13727_7-20018067-263.html Frankly I think this should be looked into for Macbook Pro 13" computers along with the iMacs.

Dec 6, 2012 9:08 PM in response to Om_Audio

I've been following this discussion for about 7 months now... .ever since my 27" iMac (mid 2011) started freezing for no distinguishable reason, along with screen black outs and artifacts, or random system shut downs. The problem was so random and so varied it was impossible to find the source.


Now, I do love Apple products, but in my experience I try to avoid dealing with Apple geniuses because generally they're not much help. I'm painting broadly here, but there's nothing worse than "Are you sure the power cord was plugged in?". That might be helpful for my grandfather, and I can appreciate that on some level; but not when I have projects that are on hold because of this issue.

Instead of going to an Apple store, I took my computer to a local computer shop that has an Apple Certified Technician. It was much easier to build a relationship with this guy and prove to him in a few short conversations that I did indeed know what I was talking about and already went through a wide variety of troubleshooting tecniques. Despite me being unable to reproduce the problem in store, he was willing to take the system and perform some tests of his own. (Now, I should mention that I do have Apple Care and I'm sure that helps make things run smoother... but technically it was still under 12 months, so the normal warranty should have worked as well.) As a expected, his tests could not detect any problem, and the iMac ran just fine for the two days he had it.

Now, here's the catch - I'm sure this local store answers to Apple in some way, but not the same way the employees at an Apple store do. "Geniuses" will eventually toe the party line because they have to; I wouldn't expect them to easily admit to an expensive problem, especially if they can't reproduce it in store. But I do believe my local computer shop guy is more concerned about helping the customer. I told him he needed to do something to it because I wasn't going to take it back without trying something. The issues seemed related to GPU or logic board, so he agreed to replace both of them. BOTH! I was happy to hear it.

But the problems didn't end there. The logic board and GPU were replaced, but after a few days of normal use my newly repaired iMac completey died and wouldn't even turn on anymore. Finally! A problem I don't have to reproduce. I called Apple Care, and after checking to make sure my iMac was actually plugged in, he recommended I send it back in for another repair. So off it went. My local shop replaced the logic board and GPU again.

Alas, this did not seem to solve the problem. When I got my computer back it started freezing on me just like it did before. I called Apple Care again, and they were still convinced that it must just be a bad logic board. Really? Don't you think there must be something else killing the logic board? What are the chances? Nevertheless, it was replaced a third time.

When I got my iMac back, it ran pretty good for about two weeks, and then half of the LCD went dim. It works, but I can't exactly use it for colour grading video productions. I called Apple Care again, and said that three repairs was enough for me. I wanted a replacement unit. He asked me if I wanted a refurbished 2011 model, or a new 2012 model. I opted for the brand new 2012 model (wierd, right?). It should be coming soon, and this whole ridiculous ordeal will be over.


If you don't have Apple Care, get it while you still can! It will save a lot of stress. They spent $2200 on repairs for my iMac before finally agreeing to replace it with a new one. I spent $300 on Apple Care.


Sorry for the ramble. 🙂

Dec 6, 2012 9:51 PM in response to Justanotherdriftwood

Pretty lengthy process to say the least. My store is 10 min away, and as far as Apple Certified Technicians go, some are good and some are bad, there is very few local Apple certified shops and if you have Apple Care it most likely will have to go through Apple online or through the Apple store. If you have been following this thread for 7 months you for sure know more than any Apple Certified Technician does! LOL I agree to a point about Geniuses first time I took it in the guy was a real A (0)! I use to work on PCs and I have worked on Apples as well, and you are right they try to point out anything but what the real problem is. I hope you get the brand new iMacs because I think one thing is for sure, they fixed the heat issue with them, which eventually cause them to fail sooner than later. I am not sure who is making Apple's logic boards, but if I were them I would look for a more reiable source! Frankly I want the hundreds of people to see me returning my iMac, shows they have a problem that they need to address.

Dec 10, 2012 9:44 AM in response to rubenlx

OK, I didn't read all 129 pages, but I've cured on my machine what appears to be an identical issue. I purchased 8GB RAM that stated it was good for 1066 or 1333mhz. I was told it was guaranteed to work (and it did for about a year) which is why I suspected other causes for the problem. Well, I took that RAM out and reinstalled the old 2GB of RAM and voila, cured. It obviously runs more slowly now but gone are the video freezing, random crashes, reboots, etc. So what I'm saying is it's possibly bad or unstable RAM. Normally when you have bad RAM the computer will make beeps on bootup or not bootup at all. This was not the case. Simply unstable video streaming.

Dec 10, 2012 10:02 AM in response to conrads

To my previous post, I did all the tricks Apple instructed. Ensure current Flash, Java, etc. Reset Safari. Reset SMC. Restart holding option-command-p-r. Repair permissions. Verify disk. Installed OSX 10.8, etc., etc., etc. Video playback would still randomly crash, stutter, freeze, reboot.... I tested various things for months but it resolved only when going back to my original RAM. Again, the previous(new) RAM worked just fine for a LONG time. It may be worth buying new RAM to try out.

Dec 10, 2012 12:28 PM in response to rubenlx

I just want to add my experience here too. My late 2010 27" has been having some serious graphics/display problems that have now seemingly escalated to hard lockups, and requiring me to restart several times a day to get a stable desktop.


It all started with some strange "pixel block" patterns that would draw and re-draw themselves on my desktop. Forcing a screen refresh (by dragging over the area, or opening a window) would clear them, but they'd re-draw a few moments later.


I'll try some of the things in this thread, especially the fan control but... If heat has already done the damage, will improving the cooling help at all?


Since it started happening, I've been from Snow Leopard through to Mountain Lion. The really bad freezes and bad startups only started happening about a week ago (a couple weeks after upgrading to ML), so none of my problems seem tied to OS.


The one time I've taken it to the Genius bar, we weren't able to reproduce it. HWT came up clean, also.


Here's a (bad) picture of the kinds of pixel-block patterns I see, this time on the pre-Apple logo startup screen. This particular example is a rare very severe case.


User uploaded file

Jan 13, 2013 3:03 PM in response to Thetis

User uploaded file


I read a few of these posts as I had similar problems with glitch graphics, screen glitches, minimizing windows and mission control seem sluggish and generally the behaviour was sluggish.


I suspected that this had to do with software because after reinstalling the osx on a new partition seemed to have solved the screen/ graphics problems, creating a new account didn't work for me.


I have resolved it by installing the software i uninstalled before the problems started, AutoCAD seem to have caused the problem for me!...


I do have though, 2 band stripe like stains (darker patches) on my display, I think the screen is defective anyway and will try to get it replaced.


I had this problem in the past and it always been linked to what is running on my machine, usually CAD software seem to trigger some issues, but not major, the machine runs beautifully also and is just the glitches in the graphics that kill the mood sometimes. Could be a conflict between Mountain Lion and software that is using the hardware in a different manner than Apple wishes?


Anyone has a similar view or problem?


Hope this post helps, but generally if a problem still exists once you have installed the OSX on a different partition then it can be assumed to be a hardware fault i think, nevertheless, very important to have Apple Care.


good luck


d

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

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