2010 iMac freezes with green squares all over screen?

[qwimjim]

my iMac started actiing up recently, and freezes 1-3 times a day now where all i can do is a hard reboot. it often happens when i'm opening a jpg, the screen will freeze and all these green squares will appear on the screen. i booted with the installation disc and did a hardware test, no problems found.. my hard drive had some issue but i also did a repair in disk utility.. but the freezing keeps happening. has anyone seen this before?

https://www.dropbox.com/s/g92i7piahgaftd1/2013-06-24 15.30.19.jpg

 

[migliore]

Console?

Have you checked the messages in console? My Early-2009 24" iMac has a similar problem where it looks like the video craps out and then the computer becomes unusable (have to reboot). My console looks like this right before "restart":
4/22/13 6:37:14.000 PM kernel[0]: NVDA(OpenGL): Channel exception! exception type = 0x8 = Fifo: Watchdog Timeout Error
4/22/13 6:37:23.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
4/22/13 6:37:51.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
4/22/13 6:38:23.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
4/22/13 6:38:43.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
4/22/13 6:39:15.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!

I think it is a bad graphics card and will be over $500 to fix, a 4yo computer.

 

[qwimjim]

Have you checked the messages in console? My Early-2009 24" iMac has a similar problem where it looks like the video craps out and then the computer becomes unusable (have to reboot). My console looks like this right before "restart":
4/22/13 6:37:14.000 PM kernel[0]: NVDA(OpenGL): Channel exception! exception type = 0x8 = Fifo: Watchdog Timeout Error
4/22/13 6:37:23.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
4/22/13 6:37:51.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
4/22/13 6:38:23.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
4/22/13 6:38:43.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!
4/22/13 6:39:15.000 PM kernel[0]: NVDA(OpenGL): Channel timeout!

I think it is a bad graphics card and will be over $500 to fix, a 4yo computer.

where can i find this log after a crash?

fortunately for me i bought this imac second hand and they had purchased an extended warranty with best buy that expires in december

 

[qwimjim]

whoops just realized all you have to do is open console was confusing it with terminal. will paste a few lines next time it crashes

 

[qwimjim]

ok just had a crash, this time i wasn't even using the computer, i left to do something, came back and screen was frozen.. could move mouse cursor around but clicking not working, nor trackpad clicking, nor keyboard.. and no green squares this time. i came back to the computer and rebooted at 11:14

https://www.dropbox.com/s/7bfeqyadmqay9mo/console.jpg

 

[qwimjim]

here's another crash:

https://www.dropbox.com/s/64qp6u49ew2dw10/console2.jpg

anyone know what to do?

 

[zuri]

here's another crash:

https://www.dropbox.com/s/64qp6u49ew2dw10/console2.jpg

anyone know what to do?

Hello qwimjim

It will be great if you can provide us with some system logs
go to apple logo -> about this mac -> more info -> system report -> logs -> panic (system crashes) report

in my opinion it is based on faulty GPU when entering into 3D mode or some graphical computing tast
it happens a lot in hd6970m in 2011 27inch imacs for example

you can also run unigine heaven or valley on your iMac and if you experience glithes and graphical artefacts or perhaps kernel panic you know it is based on GPU

 

[qwimjim]

Hello qwimjim

It will be great if you can provide us with some system logs
go to apple logo -> about this mac -> more info -> system report -> logs -> panic (system crashes) report

in my opinion it is based on faulty GPU when entering into 3D mode or some graphical computing tast
it happens a lot in hd6970m in 2011 27inch imacs for example

you can also run unigine heaven or valley on your iMac and if you experience glithes and graphical artefacts or perhaps kernel panic you know it is based on GPU

Image

thanks! but unfortunately i don't have "panic (system crashes)" in my list of logs, is it because i'm running 10.6.8?

am i to assume you didn't find anything in the console screen shots i posted?

 

[zuri]

thanks! but unfortunately i don't have "panic (system crashes)" in my list of logs, is it because i'm running 10.6.8?

am i to assume you didn't find anything in the console screen shots i posted?

I found nothing linked with error. Perhaps if you could filter console logs for openGL and for program which is making glitches it will be perfect.

What about unigine valley? No errors ?