iMac Freezing

That's not a solution, at least not for me. I would call it a work-arround. A lot of people got their graphic's card replaced and even updated and the symptoms came back. I have a 7600GT card with 256 MB with the same rom-version indicated by Micah and it does not work as it should. You still have to use an unofficial program, smc-fancontrol to avoid that your new card dies. A real solution should answer to the essential question: What's the reason for the symptoms? Up to now we haven't found the answer to that question.

Nevertheless, your system is running, that's great, congrats.

What about people with Ati video cards? Same problems with those.

Agreed, it's only a temporary fix. Venting must be increased or at the least SMC Fan Control has to be run to keep the replacement card from over heating over the coming months/years, at least that's my opinion.

Despite what people keep saying about "cards running in acceptable temp ranges" I still think the cards overheat inside the nearly ventless case of these iMacs and expire because of it.

For all we know, the problem is that the heat sensors are reading the wrong temperature and it's screaming hot inside the case.

The point is, the card isn't the problem when you buy the computer. Something, somewhere, for some reason is ruining the cards as time goes by. I think it's heat. Others think it's the motherboard. Whatever it is, apple is not going to do anything about it. They don't care, they already have our money and tough nutz for us. Like I've said before, Apple is becoming like Microsoft: They do what they think is right for THEM, not for us their lowly customers. We're just in impediment to how "great" they could be, if we'd just shut up and get out of the way they could be the best computer companies ever!

Not.

Hello Micah D.

A sensor is a sensor and reading the data out of the sensor is trivial. If there would be a problem with the sensors I believe that Apple would gracefully offer to replace the sensors. It's the first time somebody says that the sensors are reading "wrong temperatures". But all we are doing is "guess-work", you believe, I believe. My case was "screaming hot" up to the moment I fixed the overheating of my power supply by removing foam isolation material. My case feels ok now, but my gpu doesn't. I have to use fancontrol to avoid freezing.

My current temperatures:
CPU A: 38 ºC
Ambient: 30 ºC
GPU: 45 ºC
GPU Diode: 51 ºC
GPU Heatsink: 43 ºC
HD Bay 1: 43 ºC
Optical drive: 40 ºC
Power Supply 1: 54 ºC

My power supply and my harddisk reached temperatures of over 80 and 60 ºC respectively before removing the isolation foam that prevented the air to circulate inside the power supply enclosure. If we could reduce the problem to defective sensors or erroneous readings things would be easy for us because this would be an unrefutable proof. The temperature readings are ok, what isn't ok is that I have to use a fan control program to lower my temperatures to that point to assure the reliability of my machine. Without fan control my temperatures rise more than 10 ºC (still within acceptable limits) but beachball of death shows up...

maitaimai wrote:
Hello Micah D.

A sensor is a sensor and reading the data out of the sensor is trivial. If there would be a problem with the sensors I believe that Apple would gracefully offer to replace the sensors.

Say what? So are you suggesting a sensor can't be wrong? And furthermore, if it's "trivial" what the sensors are reporting why are you listing all your internal temperatures _according to the sensors_? It's not trivial at all. If the GPU fails at a certain temp, but we all think our iMacs aren't getting that hot it's not trivial at ALL what the sensor say. It's integral to the problem: If the sensors are reporting incorrect temps we have NO idea if our computers are getting "too hot" or not.

It's the first time somebody says that the sensors are reading "wrong temperatures".

Please don't misquote me. I never said that I think that's the problem. I said that for all we know it COULD be the problem, we have no idea if the sensors are correct or not. We're all just assuming the sensors are reporting the right temps.

My case was "screaming hot" up to the moment I fixed the overheating of my power supply by removing foam isolation material.

OK then, proving my point.... the computers are getting too hot inside and frying the graphics cards is my bet!

A sensor is a sensor and reading the data out of the sensor is trivial. If there would be a problem with the sensors I believe that Apple would gracefully offer to replace the sensors.

Say what? So are you suggesting a sensor can't be wrong? And furthermore, if it's "trivial" what the sensors are reporting why are you listing all your internal temperatures _according to the sensors_? It's not trivial at all. If the GPU fails at a certain temp, but we all think our iMacs aren't getting that hot it's not trivial at ALL what the sensor say. It's integral to the problem: If the sensors are reporting incorrect temps we have NO idea if our computers are getting "too hot" or not.

It's the first time somebody says that the sensors are reading "wrong temperatures".

Please don't misquote me. I never said that I think that's the problem. I said that for all we know it COULD be the problem, we have no idea if the sensors are correct or not. We're all just assuming the sensors are reporting the right temps.

My case was "screaming hot" up to the moment I fixed the overheating of my power supply by removing foam isolation material.

OK then, proving my point.... the computers are getting too hot inside and frying the graphics cards is my bet!

I had an additional problem with the side effect that it was about to fry my harddisk as well. But this is not necessarily related to the gpu problem. Moreover: for this reason I started to use smcfancontrol a few month after buying my iMac. If the proof for you consists in the affirmation that the temperatures meassured were to high but meassured correctly, well, take if as a proof. I myself could accept failing sensors as a possible cause but with a real low ranking within all possible causes. And moreover:

1. This is easy to test with additional and independant sensors
2. And if so: The possible erroneous derivation seems nearly the same for all of us
3. For this reason it would be easy for Apple to adapt the fan speed with firmware and software updates to correct the problem (like they did with a mac book series)
4. They haven't done beside the fact that I'm convinced that they closely follow our discusssions and that they are aware of the symptoms. (Probably they know about the cause as well and that it would be expansive for them to acknowledge and address the problem properly)

All of what I'm offering is just speculation applying a dose of deduction and a dose of analogic thinking. To introduce defective sensors into the discussion simply doesn't make much sense to me.

I too had all these symptoms, read most of these posts and yesterday I changed out my vid card. Everything works fine now thanks to the many helpful posts.

A few observations for those who will do this @Home:

a) I got my card from dvwarehouse for $230. ($23 to ship to Alaska)

b) I saw no need for application of thermal paste (I have had to use it before when I did surgery on my old iLamp, so I know what it is and what it is for).

c) When re-installing the repaired motherboard I would connect the optical drive cable (the amber/orange one) to the board before screwing it down. It was rather flimsy.

d) I am continuing to use my SMC Fan Control PrefPane. It is my opinion that this all started after my 10.5 update and the original settings for fan speed did not meet the demands of the new OS. I may be wrong, but I'm goin' down trying. It is the best I can do since Apple is stonewalling that there is this problem out there.

I have had to crack every iMac I have ever had.

@ tyc314159: Great post!. I like the last sentence. It does fry.

I have asked multiple times and still no one is posting at our iMac topic on GetSatisfaction. Here is the link again: http://getsatisfaction.com/apple/topics/2006imac_graphics_card_crashfreeze

I've also begun to have this problem. My computer seems to be running a little hotter over time. Now, I get graphical glitches whenever I run anything that's is graphically intense. Full screen movies, streaming video, games, etc... The glitching begins with the horizontal lines and then if I don't give the video card a break, it will eventually freeze/crash.

I haven't have many full system crashes. It seems more like the video card will crash. It will go completely to a black screen or the entire screen will be distorted, but I can hear the mouse in the background. I can usually bring it back by manually putting the computer to sleep and letting it cool down a bit.

However, it is obviously deteriorating as video that used to run perfectly fine is now causing these issues to arise.

It is a very good idea for everyone who has this problem to make at least 1 posting on the GetSatisfaction thread, so that there is an independent record of the problem.

Because Apple controls this Apple Discussions area, it's quite possible for them to delete the whole of this thread at any time (as I think they have done with other threads in the past), which would mean that all the useful input that has been added to this thread would be gone! So, it is important that there is an independent record of the problem.

Zachnap wrote:
I have asked multiple times and still no one is posting at our iMac topic on GetSatisfaction.

Now you know why Apple isn't going to do anything about this problem, and also why any discussion of a class action is IMO wasted breath. People don't actually care enough about these kinds of things to even sign up for (yet another) website login, including me. I'd rather just figure out the direct solution and fix it myself, and if that doesn't work I'll buy a new computer.

Most people aren't willing to put themselves through even mild discomfort to deal with stuff like this, mainly because no one knows what the actual problem is. When there's a clearly defined issue that one can put one's finger on people are more likely to react. But when it's vague people figure "Maybe I don't even have that problem, maybe it's something else" and go about their business.

So Apple will continue to ignore this entire issue, because it's in their best interest to do so. Responding means admitting there's one problem and then dealing with it. Ignoring means not having to do anything.

And no, they no longer care about "losing customers" apple has now become big enough that they can afford to make a certain percentage of their own customer base angry and not worry about it. Tough luck for us, apparently when apple adopted the Intel chip set they also decided to adopt a Microsoft-like disrespect for their own customers.

New information revealed.
1.) I let Apple Service replace my 7600GT with a new one which had a new revision.
Same errors as before, but sometimes crashes while booting.

2.) Now I went back to the Apple Service Center and told them my story. They ordered a new logic board AND a new 7600GT and installed them. I verified that by checking the serial number of the logic board. It is a new one. BUT errors are getting worse. Now the horizontal lines and the crashes even come at random. I just had one while running NO programs at all an just pointed the mouse cursor over the dock.

3.) It has nothing to do with my system. I booted from a Drive Genius CD to check my harddrive. Guess what? Same crash while using Drive Genius. Then I tried to boot via FireWire from an external OSX system. -> Crash while booting.
Tried booting Bootcamp Vista to see what happens there -> Blue Screen of death OR sometimes just a black Screen. But no system response any longer.

4.) I used TechTool Pro 5 to check my Hardware. No errors found. Apple Support Guy told me his Hardware Test Tools showed no errors, too.

Most of the crashes are random. Multiwinia seems to be one application which crashes my iMac for sure.

I do not know what to do next. There is nothing more to replace, it just seems to be a production issue in every card.
Any chance to get a replacement to a newer imac revision? I would even pay a premium to get an ATI card or a newer NVIDIA card.