iMac Freezing

If your machine is still under warranty, I would run, not walk, it to an Apple repair center! 🙂

If not, you might want to try the smcFanControl, or another fan-speed control app. (but will likely be a temporary fix). Also, try running the hardware test; resetting your pram & verify/repair permissions.

yup, i've run the hardware test and everything comes back ok. i've reset the pram and i've also verified/repaired permissions and the drive. recently, i have done a clean install and used the combo updater to update to the latest version. my imac is still under warranty until april, but since i'm about an hour and a half away from the nearest apple store or repair center, i'm going to see if i can call first and see if they'll do anything. thanks!

You likely already know this, so bear with me while I (who-waited-until-warranty-was-looong-expired-before-taking-in-for-repair) point it out anyway .... if it does turn out be a bad graphics card (or logic board), that's a $1,000-ish repair. So if need be, it would definitely be worth the long drive(s) to get it resolved before warranty runs out.
Good luck!

This problem has been driving me crazy for over a year now. The Geniuses at the Apple Store don't seem to have the solution. They run a series of tests and tell you the logic board is at fault. Twice they have replaced the video card as well.

Like a lot of people, this has started when I play World of Warcraft. The design of the iMac is poor, and it does not filter out heat efficiently from the video card. That's where the primary issue lies IMO, and unless you want to cut a hole in the casing and put a fan in there, you are probably going to continue having these issues for the life of your iMac when doing a lot of video intensive stuff, such as WoW.

The results of the lack of heat dissipation are logic board, video card/video ram failures. I've had it all replaced twice in the past year at my local Apple Store. They have replaced the logic board a 3rd time. I hope you have apple care, because like someone said, it's almost $1000 per pop if you don't. I'm so glad I did make that investment. I've had over $3000 in repairs to my $1800 iMac.

The first thing I did when I started having problems, based on a conversation with Apple Tech Support was install SMC fan control. I found out running WOW on the default fan settings caused an internal temp of around 140 degrees after about an hour of playing. Not good for any computer electronics. I maxed out the fan speeds, and before I had the 1st logic board replaced, I was still getting temps of about 110 - 120. So, if you are having issues already, SMC is not going to fix them. Now, after the 3rd time, I still run SMC, but I still get temps in the 105 range with a good (or at least new) logic board immediately when starting up WOW, and I still start having video issues after about an hour or less of playing. SMC is NOT a fix for this issue if you are playing WoW.

If you run tech tool deluxe after playing WoW, you will see that your video ram fails tests.

Just my opinion, the logic board is what goes bad first, but it's only a symptom of the problem, and replacing it is not the solution. But until someone at Apple is willing to go past only treating the symptom, and starts looking for a solution, then you (and everyone else) are going to continue having problems. This was my first iMac, and I love it for some things, but it's very obvious that if I want to continue gaming, an iMac is NOT the product for that.

You've got the same model and issues that I have. I've also been told it's not a known problem, yet they do have "resolutions" for the "unknown" issue that isn't affecting anyone else.

It's only not a known problem because they are refusing to acknowledge that there is a problem.

Just to add on to what I just posted. Do NOT walk away from the Apple Store without checking your internet connection as well. Even if it works initially, navigate to a few webpages and watch your airport icon. Open the internet connect there as well and verify your signal levels are maxed out. All 3 times I've had this problem fixed, my airport was either disconnected, or in this last instance broken (snapped connector or something). Maybe it doesn't happen to everyone, but for me it's been 100%.

I suggest those still under warranty to go to the Apple store and tell them your situation. I'd imagine they'd be willing to replace your iMac, especially if it has been repaired multiple times. I personally did not request for a replacement but did express concerns about the downtime. The Genius listened and was able to meet my needs, by giving me a new and working iMac. I've had the replacement for about a month now. So far no freezes or random shut downs.

I've gotten nowhere when talking about a replacement. The geniuses there are great, they listen well, they have explained what they have done, but a replacement seems to be a non-starter. I'm having these issues start again (just had the last logic board/video card replaced in December) and I'm hoping that maybe this time they will consider a replacement.

But definitely, if it's under warranty, get it in ASAP.

I tend to agree with other posters that this is a heat issue.

As an aside, one of the Apple technicians I talked to said he is aware of a World of Warcraft/Mac problem being investigated by Apple's engineers, but he had no information other than that -- that it's being investigated.

While there might very well be a specific problem related to WoW, I am inclined to think it just SEEMS like it's WoW related because that's where the heat/graphics card problem first begins to manifest itself because of the video demands of the game. Eventually, it begins to show up outside of WoW, as what I presume is the degradation of the graphics card progresses.

not surprisingly, the people at the genius bar do not buy into the commonly accepted belief that an extended warranty is not needed, and that if a device is defective, it will fail within the initial warranty period. for apple to have such a lack of faith in the durability of their own products is astounding.

i'm hoping that after speaking with customer relations, my repair fee will be waived. i can assure you that applecare won't be an afterthought because i have absolutely no faith in this product.

So, I'm an owner of a mac-lemon now? My iMac started freezing and screaming after about 40 minutes of streaming video and it has now been 6 days without it because the genius bar cannot seem to get the parts to fix what they think is the problem. They do not contact you with test results unless you complain and only then do they call to let you know that they "know nothing".

Now I read through the feed back and discover that I am not just imagining it taking longer to boot up. Are you kidding me?

I thought the switch to Mac land was going to produce a more reliable system for my work (Photoshop) but here I sit with no machine (because some "genius" has it)and no way of making the images I depend upon. Thanks, APPLE, I appreciate being a guinea pig.

Hello Folks,

Gteetings from The Netherlands and yup, you can add me to the list... :-< I'm on a 20" 2.16GHz iMac with an ATI Radeon x1600, bought september 2006.

Looks indeed like the GPU is going on the fritz. Horizontal lines (like a tear in the screen, they go away when resizing the window they appear in), random & sudden square/triangular colour blotches, smeared screens, funny graphics artefacts, complete white-out of the screens (it like slowly smears out into an all white screen, then freezes. Sound ambles on a bit afterwards, then dies too), now daily freezes. When using the GPU like in watching several youtube clips, I can now almost wait for the freeze to occur. Another example of evidence for bad GPU behaviour is Photo Booth: the video in the Photo Booth window freezes within seconds, and only unfreezes if I move the window around, to do it again seconds later. smcFanControl makes no difference. iStat Pro: GPU diode at 36°C. All this has begun a few months back, and it's slowly but surely getting worse. Some more stats:

Hardware Overview:

Model Name: iMac
Model Identifier: iMac5,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.16 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 3 GB
Bus Speed: 667 MHz
Boot ROM Version: IM51.0090.B09
SMC Version: 1.9f4
Serial Number: CK6351M ** <Edited by Host>

ATI Radeon X1600:

Chipset Model: ATY,RadeonX1600
Type: Display
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 128 MB
Vendor: ATI (0x1002)
Device ID: 0x71c5
Revision ID: 0x0000
ROM Revision: 113-xxxxxx-139
EFI Driver Version: 01.00.139
Displays:
iMac:
Resolution: 1680 x 1050
Depth: 32-bit Color
Core Image: Hardware Accelerated
Main Display: Yes
Mirror: Off
Online: Yes
Quartz Extreme: Supported
Built-In: Yes


So there you have it. No AppleCare: after being on the Mac since 1986 this is the first one to give me any trouble.

Grrr.

Hi all,

I have the same kind of problem...

Very slow start, sometime, no start at all.

When it succeed to start and boot, it oftenly is slow to the point of freezing.

It first started with crashing Path Finder software ... Since then, it keeps crashing.

I still dare to believe that hard drive might be the cause ...

Can anybody help me ?

Hi all,
here's a way to hide almost all sympthoms:
1. use iMac Fan Control (if you want version build especially for iMac late 2006 - email me)
keep GPU under 40 degrees Celsjus

2. turn off Quartz Extreme. Here's a way to do it by FRED (many thanx)

Quartz Extreme can be ratehr easily disabled, especially since you have installed the developer tools already.
Go to the following folder :
System -> Library - > FrameWorks -> ApplicationServices.framework -> Versions -> A -> Frameworks - > CoreGraphics.framework -> Versions -> A -> Resources
In this folder, you will see a file called : "Configuration.plist".
Drag it to your Desktop and control-click it. Choose "Open with..." and select "Property list editor".
Click on the arrow in front of "GLCompositorConfiguration" and then select the "GLCompositorMinimumVRAM" line. Change the default value (typically : "16") to something higher than the VRAM size of your graphics card. To be on the safe side, I entered "512" as my video card has 256MB of VRAM.
Close the file... of course saving the changes.
And then replace the file in the System folder with the one you just edited.
Restart your iMac and open the Dashboard. Drag any widget to it... and Voilà. No more Water effect, which means Quartz Extreme is disabled.

Regards.

FRED

After an update the patch schould be applied again.

iMac will still crash with applications that use Open GL, but in many others it works quite well.

I still keep the faith that Apple will start an exchange program for mainboards

regards from Poland
Marek Szukało

Hi,

As to option #1: never hurts IMO in light of what we suspect could the problem (fried GPU's). I'm running the CPU at a lower limit of 2000rpm, which seems to keep the CPU and GPU diode at just above 30°C.

as to option #2: brilliant tip, however being without Quartz Extreme won't do for me. I've changed the default valude of GLCompositorMinimumVRAM from 16 to 64 (using TextEdit, which works just fine) on my 128Mb ATI Radeon X1600 and -so far- things have improved considerably (see my earlier post in this thread).

We'll see how things hold out. Nevertheless, in spite of this apparent fix (?) I believe it's still a sick puppy that's standing here on my desk, so we haven't seen the last of it yet 😟

Regards,
Jurgen

Message was edited by: Jurgen van der Pol