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Q: NVDA(OpenGL): Channel exception!
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Aug 25, 2009 12:09 AMby tom.clarke,For what it's worth, I'm also experiencing frequent system hangs, occasional graphical aberrations and I'm seeing tons of NVDA(OpenGL): Channel exception errors in my logs.
I reported the bug, as suggested earlier in the thread. I just thought I'd add my name to the list of people with this problem. I suspect that on another desktop OS, this would be causing something like a BSOD. Grrr! -
Aug 27, 2009 7:20 PMby quantumpot,I am absolutely appalled by Apple's lack of commitment to solve this issue. I too have been having these issues and so far the boards have yielded no luck.
At this point I really don't care if it a software issue, hardware issue (apple) or NVIDIA issue. Apple should at least acknowledge the issue and not leave us hanging.
I am a big fan of Apple after having gotten rid of all my PC at home about 3 years ago. But this issue has made me extremely skeptical.
All I am looking for is an acknowledgement and a suggestion from them!! -
Aug 28, 2009 8:53 AMby dedward,Well, I'm glad I finally looked at the logs and did some googling, now I know I'm not crazy.
My imac 24" with 7300GT does the screen-freeze and lock-up all the time- often unrecoverable.
I can usually SSH in and reboot and/or look at log messages, but not always.
The problem started about a year ago, but only when playing some 3d games... now it's getting progressively worse.
Come on Apple... let's have some kind of comment here. -
Aug 28, 2009 11:16 AMby cksnod,In my case I have finally determined that it is a temperature issue--at least that is how it manifests itself on my system. I am not able to either start up or wake from sleep (after sleeping at least 1-2 hours) without encountering the openGL channel exception with lockup/pixellation of my screen. But if I boot into Safe Mode, let the system warm up 10-15 minutes, then reboot, I have no problems for the rest of the day. Until the next cold start. I've removed the video card (did not observe if there was bulging of the capacitor because I did not read about that issue until I'd already put the system back together), dusted it off, cleaned the contacts, and re-installed. Made no difference. I did notice that one of the capacitors was tilted in an odd manner, almost as if it had been bumped.
I'm to the point where I'm ready to order a new video card. Think I'll get the ATI Radeon HD 3870 as was recommended by a previous poster. -
Aug 29, 2009 4:37 AMby rdapple,I do not believe this is a hardware, nor a temperature issue, but a software (possibly driver) issue.
Reasoning:
Rebooting to Windows via Bootcamp
Installed & ran Furmark Graphics Card Stress Test
Reached 84C (max attained temp. on graphics chip, would not go higher)
Several minutes at 84C cause zero errors/BSOD/video corruption in Windows
Rebooting to Mac OS X 10.5.7 or 10.5.8
Watching YouTube video: System Freeze after 5 minutes
Playing World of Warcraft: Random Freezes and video corruption & lock-up requiring hard reset
Conclusion:
This is a software issue related to Mac 10.5.7/8 Nvidia Graphics card drivers.
Setup:
MacBook Pro 15" (3,1) C2Duo 2.2Ghz, 3GB Ram
Boot ROM version MBP31.0070.B07
SMC Version: 1.16f11
Graphics card:
Chipset Model: GeForce 8600M GT
Type: Display
Bus: PCIe
PCIe Lane Width: x16
VRAM (Total): 128 MB
Vendor: NVIDIA (0x10de)
Device ID: 0x0407
Revision ID: 0x00a1
ROM Revision: 3175
Furmark: http://www.geeks3d.com/20090703/furmark-1-7-0-the-bad-boy-of-graphics-cards-util ities-is-back/ -
Aug 29, 2009 4:54 PMby Witch,@rdapple: You know that apple has a replacement program for the 8600GT?
Question to all: Does anybody know if the fonts are saved in graphics card?
I noticed that when I get the error in topic sometimes when the iMac unfreezes for some seconds I can scroll back through All messages in Console app and every single letter/digit/sign ist displayed wrong. But same sign is represented by same wrong sign while scrolling back. Only after next freeze text not yet displayed before that freeze will be shown with different representation.
So my conclusion of that is: in this case whereever the font map is saved in mem there mem content is changed on each freeze. But for me it does not look like the changed mem means total destruction. It just looks like some other sign is shown instead of a "0" or "N"" or whatever.
Looking through the two threads (this one and the iMac Freezes thread again, I found that the answers of different Apple supports look so similar that they must have a text in their support database for the answer on this issue saying that like: "If Apple Care stil applies: replace somehting until customer does not come back or Apple Care time is over. If no Apple Care: Tell Apple is not aware of an issue, unknown problem."
At least a lot of people got replacements for graphic cards and logic board in their late 2006 iMacs, where nothing seems to solve the problem for a longer time. So they must be aware of that problem. -
Aug 31, 2009 5:59 AMby al_broccoli,Witch wrote:
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.
As the link you post says, it's a late 2006 24" iMac. I'm not sure what more information you're looking for.
And just to add a little more info, after replacing the card, I can make it crash with the same errors before by running the Multiwinia Demo, or by doing something graphics-intensive in Photoshop. Before replacing the card, I had errors all the time while doing much of nothing. Now it's only when taxing the GPU, but they're still there, same errors as before.
It's not much of a Mac if I can't do Photoshop. -
Aug 31, 2009 7:06 AMby al_broccoli,Just a note - the iMac Freezing thread was archived - I'm not sure why, if not in an attempt to stop the discussion or to minimize it's reply/view counts. I created a new thread as a continuation of that topic here:
http://discussions.apple.com/thread.jspa?threadID=2136365&tstart=0 -
Aug 31, 2009 8:33 AMby al_broccoli,Michael Hammarnejd wrote:
Looks non-archived to me...
If you're referring to the link I just posted here, that is the thread I just created, so yes, it's "non-archived." It, however, is the continuation of the iMac Freezing thread, which is still archived, which means no one can post any longer in that thread. -
Aug 31, 2009 12:40 PMby Mechanic man,Dear Michael,
And again all sorts of problems with NVidia graphics. The combination Apple and NVidia was a disaster from day one, so don't even think Apple is going to solve any software issues. They simply can't!
Although nice looking, I refuse to buy those NVidia polluted Apple laptops and I'm glad my company's 2008 iMac (bought new last month from an overstock and much preferred over the 2009 basic configurations) has ATI graphics, because that fact alone let me - and my boss - sleep a whole lot better!
And my private G5 as mentioned below, where I didn't have any choice at all? Well: ghost images, etcetera, etcetera... you get even used to it over time.
Best regards and a lot of success,
Robbert
