Mid-2011 iMac locking up
Folks, almost every day I experience the iMac locking up requiring cycling the power to reboot. I checked the log from the console each time it happens and this is what I am seeing around the time it locks up. It references "slot 1" but not sure if this is related to memory. I have run several memory test using memtest and rember and the memory always passes. Any suggestions on what is happening and what to do would be most appreciated.
Here is a sample of the console log message:
6/28/12 11:26:13.000 AM kernel: IOSurface: buffer allocation size is zero
6/28/12 11:26:13.000 AM kernel: IOSurface: buffer allocation size is zero
6/28/12 11:26:19.000 AM kernel: IOSurface: buffer allocation size is zero
6/28/12 11:26:19.000 AM kernel: IOSurface: buffer allocation size is zero
6/28/12 11:27:02.000 AM kernel: IOSurface: buffer allocation size is zero
6/28/12 11:27:02.000 AM kernel: IOSurface: buffer allocation size is zero
6/28/12 11:27:04.000 AM kernel: IOSurface: buffer allocation size is zero
6/28/12 11:27:30.000 AM kernel: ** Device in slot: SLOT--1 **
6/28/12 11:27:30.000 AM kernel: ** GPU Debug Info Start **
6/28/12 11:27:30.000 AM kernel: 0x00006741
6/28/12 11:27:30.000 AM kernel: 0x0000008f
6/28/12 11:27:30.000 AM kernel: 0x00000001
6/28/12 11:27:30.000 AM kernel: 0x00000018
6/28/12 11:27:30.000 AM kernel: 0x0000a880
6/28/12 11:27:30.000 AM kernel: 0x00000001
6/28/12 11:27:30.000 AM kernel: 0x00000001
6/28/12 11:27:30.000 AM kernel: 0x00006741
6/28/12 11:27:30.000 AM kernel: 0x00000001
6/28/12 11:27:30.000 AM kernel: 0x00000015
6/28/12 11:27:30.000 AM kernel: 0x00000000
6/28/12 11:27:30.000 AM kernel: 0x00000001
6/28/12 11:27:30.000 AM kernel: 0x00000047
6/28/12 11:27:30.000 AM kernel: 0x00000000
6/28/12 11:27:30.000 AM kernel: 0x00000001
6/28/12 11:27:30.000 AM kernel: 0x00000058
6/28/12 11:27:30.000 AM kernel: 0x00000012
6/28/12 11:27:30.000 AM kernel: 0x00000001
6/28/12 11:27:30.000 AM kernel: 0x00000055
6/28/12 11:27:30.000 AM kernel: 0x00000000
6/28/12 11:27:30.000 AM kernel: 0x00000001
The kernel messages go on and on so only pasted the first part of it.
Thanks again for any help.
Duffy
iMac (21.5-inch Mid 2011)