iMac Freezing

I don't think so, I estimate that about 200 - 300 people have reported this in various forums. we have the largest topic in the Apple Discussion Boards - larger than the 4850 HD card issue that Apple acknowledged as software. I have found 3 blogs along with comments from many people, there are 3 or 4 other topics on these boards about the issue.

Do 1 in 5 people with this issue actually post on the net or 1 in 10, 1 in 3, who knows?

I'd estimate that a few thousand people have this problem.


The whole mainboard must be replaced in the 17" and 20" models.

Message was edited by: Zachnap

Because GPU is soldered to mainboard in my case: iMac 20 late 2006 Radeon X1600.

MarekSz wrote:
Because GPU is soldered to mainboard in my case: iMac 20 late 2006 Radeon X1600.

But that doesn't mean the motherboard is the problem.

And you don't have to replace the motherboard to replace your video card, you have to find someone who can solder a new video card onto your motherboard. Which I wouldn't bother with, personally.

On what basis do you assume that it's only the graphics card? Why do you state that nobody indicated the motherboard as a problem as well. I did, others did. Your assumption may be correct, but it's still an assumption, nothing that we can take for granted. You replaced your graphics card, it worked, it stopped working. Others did, with new ones, it didn't help either. If you could offer an explanation that explains our problems 100%, ok, but you can't. So please, don't be that categoric.

Afaik Apple replaces only a newer graphic card on MacBook pro with Nvidia 8600M GT (TS2377).
I cannot find any document telling that the problem with 7300 GT is aknowledged by Apple. So I am not sure, if the article on Hardmac linked above is correct.

There are different products and graphc cards with problems:

- One ATI Mobility (driver problem ist seems) - Error containing "wait for_rbspace" - there is a thread about that her, too.
- The Nvidia mentioned above (card faulty)
- Nvidia 7300GT and 7600 GT (kernel panics in 10.4 and the NVDA - Errors containing "NVDA(OpenGL): Channel exception!"

Some other problems can be solved by choosing different settings.

I encourage you really to search for Errors in syslog:
- Open Console.app from utilies (German: Konsole.app
- open the list of logs pressing the button left
- choose all messages
- then filter by "NVDA" or "ATIRadeon" to see the latest messages in Logs
Complete current syslog (system.log and system.log.x.bz2 for old versions) are a bit down in /var/log

Message was edited by: Witch

I'm having freezing problems with my intel imac 2006. So here's the rub. I can start the computer, but it randomly freezes. It does this when I boot from a cd, and external hard drive so it has to be something more internal. Some other problems I was having is that I would get a few lines on the screen. I was wondering if this could be a power supply issue, or a graphics issue. I don't have any applecare left but I was still looking at maybe saving everything. If the graphics card is dead i guess I'm out of luck but if a bad power supply can cause random freezes, It would be worth fixing.

maitaimai wrote:
On what basis do you assume that it's only the graphics card? ... please, don't be that categoric.

I wasn't being categoric at all, and I didn't say that I assume it's only the graphics card. On the contrary, my post was pointing out that the OP shouldn't assume it's the mother board, particularly when most evidence points to the graphics card. I've seen ZERO evidence that it's the motherboard, where I've seen tons of evidence that it's the graphics card, including my own experience: The graphics card that I had that was working fine and a problem completely unrelated to what's going on in this thread. Other than that, it's installation 100% solved my issues during the time the card was making a good connection.

I do happen to think it's the graphics card, nothing more. But the post you're referring to doesn't state that categorically.

You might try reading through this thread, everything you've posted about has already been covered.

One symptom I am getting that I haven't heard anyone else mention is the TrashBin emptying extremely slowly after leaving my comp on for a few hours. It will literally sit there emptying for hours and hours - this could be a sign that it is the logic board. Also, the beachball... I guess it could be waiting for graphics processing but seems like it is more of a logic board/processor thing - maybe.

Witch wrote:
Afaik Apple replaces only a newer graphic card on MacBook pro with Nvidia 8600M GT (TS2377).
I cannot find any document telling that the problem with 7300 GT is aknowledged by Apple. So I am not sure, if the article on Hardmac linked above is correct.

http://forum.macbidouille.com/index.php?showtopic=307904&st=0&p=3062643&#entry30 62643

It isn't the same 7300 as in the iMac. Different design, same chipset.

I do not get the TS document in search and it gives 404.

But this makes me even more curious about how the support can tell me they aren't aware of any problems with Nvidia 7300 GT. And for sure: no help for the iMac Users.

Zachnap wrote:
It isn't the same 7300 as in the iMac. Different design, same chipset.

Ok, It isn't the same 7300 as in the iMac but the described problems in Mac pro are the same in ours Imacs.

I agree. I haven't noticed this specific symptom (Trash bin emptying slowly), but I have noticed random things, which have nothing to do with the graphics, going very slowly. Especially after the computer has been on for a while.

It feels like something else in the computer is going besides the graphics cards. Logic board / RAM? I don't know. I still can't get anything to fail on diagnostics.

What we have for the white iMacs:

- Two different graphic card manufacturers implied
- three or four different card models fail
- all "inch models" affected with different logic boards based on the same design principals and propably produced with the same raw material
- Repair seems not to fix the problem. You have to speed up fans to avoid or postpone that your card fails again under normal (Micah proposes above normal) conditions

My conclusion: There is something more involved, not only the graphics card. This something ranges from drivers, firmware to logic board. My candidate is the logic board for the simple reason that firmware and drivers can be fixed and for the reason that the problem is not specific to OS X.

What we could do:

- Buy a graphic card (not one of the series affected by the problem) that fits into the 24'' iMacs with drivers for Windows, install Windows and see if the machine fails after some time (it fails under Windows as well right now). My machine is still working fine and I won't touch it but testing a different graphic card model is a good test to determine if it's only graphic card related