NVDA(OpenGL): Channel exception!

I called apple Germany yesterday.

The support said:

- They are not aware of a problem with iMacs
- There is no replacement program like now for MacBook and Georforce 8600
- In my IMac the graphic card cannot be changed, the complete logic board would be needed to be replaced (not sure if that is true)

Replacement of logic board might cost about 2/3rd of what I payed for the iMac, so that is not really an option, especially as I have no clue, if the problem will persist afterwards.

As System Upgrades change the problem we still do not know now if it can be solved with other driver. As smcFanControl seems to delay the freezes, there is hardware problem at least. But why then does the behaviour change with system upgrades? From kernel panics to less often and more often freezes after each OS Update/upgrade?

Wenn I had the kernel panics on OSX 10.4 I sent apple lots of crash reports.
When it all started LL as the company behind SL said, it is an apple fault (though others had same problem) while Apple blamed the application programmers.

Now that there are many threads and it applies not only to using Second Life or games with extended graphics usage we get some more info from each other but still nothing at all from apple.

I found some news that apple will not use Nvidia any longer due to problems at beginning of august and and a denial from apple at 7th of august. and there is an article which seems to confirm, that there is a hardware problem: http://www.9to5mac.com/nvidia-display-cards (you may want to have a look at the sources linked there, too).

If anybody knows, for which iMac 24" this ( http://sap-dba.blogspot.com/2009/08/replacing-video-card-in-late-2006-24.html) would work, it would be really nice if you told us.

Afaik only the 7300 GT and the 7600 GT wil fit into the iMac with exchangable graphic card.

Awareness: One of the threads here abouzt freezing issues has more than 30,000 views. And as I pointed out Apple and Nvidia seem to share costs for excahnging graphic cards for apple care users and for the MacBook.

But some other news. I did search a program getting the temperatures to log them.

Then I started pixels from the Developer Tools Application examples in OpenGL section.
I was watching video and the computer had been freezing night before but was not shutdown as I did not watch and it wanted me to close a window.
I was watching video before and temperature of temp diode on graphic card was at 52°C.
Nothing did happen, when running pixels.
Then I closed pixels and ran Second Life, went to same point where it froze last night and did the same I did there before - nothing happened. Temperature of temp diode was now at 56 degrees.
Then I did fly to another place with my avatar in Second Life and walked and watched. Was not high graphics load though. But it started to freeze after some minutes (temp now at 57°C for just a moment and power supply at 59).

Screen got damaged totally including menu. I have been able to start screnshot program in time this time and got some nice screenshots from what happend then.

After a while (7 minutes later and after loosing the connection to SL Server screen started to show some parts of the windows on it again and step by step parts of the menu. But the Apple in the left now (half an hour later) is still a black square. Syslog (Console/All Messages) has stopped to show NVDA Errors long time ago. Beside the Apple not showing up, I cannot access any of the menus, it shows the shadow of the nenu windows, but no background and no content, For some of them I can click and see the menu content for a moment, but it does not stay.

I am quite sure that what happens just now not having NVDA errors any longer is not an Nvidia problem but a problem with my system not working properly any longer.
Am I right that this is a sign for not only being a graphic card issue but also a kernel problem?
For me it looks like mem being overwritten somwhere. And we should not forget about the issue going worse, when upgrading to 10.5.7.

I really have been thinking about changing graphics card. But when it comes back then? 400 Euro for nothing?

And I changed to Mac not to have costs for exchanging things all the time like with my PCs prior to 2001.

BTW: If I restart finder now, it alwas opens finder windows, I have been closing before. Can that be a graphic card issue? It must be an OS issue being triggered by the freeze before.

10.5.7 made it just worse for me. But the error in the topic is still the same as it happend less often up to 10.5.6.

Verify which erros you have in syslog like this:

Open Console.app from utilies (German: Konsole.app)
open the list of logs pressing the button left
choose all messages
then filter by "NVDA" to see the latest messages in logs

Winfer: That does not give much hope.

About Software or not: Whatever you start, it uses a driver for the graphics card, and the Nvidia driver will not be much different for windows and OS X.

I may have asked that already: Did anybody gettign the errors and damaged screen try to set another graphic card driver using OpenGL profiler? It sets the driver to use with an app. The bad: you have to do that every time using the app again.