Since upgrading to OS X 10.8, aka Mountain Lion, my Mac Pro has been suffering from kernel panics. The solution has been to replace my two NVidia GT120 graphics cards with a single ATI 5770 graphics card.
The problem appears to effect those running multiple monitors and using the Apple issued GT120 graphics cards.
For me, the kernel panics occurred while browsing the web with Safari. Often the kernel panic occurred as I scrolled down a page. It did not require a complex web page; just a web page containing plain text was enough. It was not caused by Flash or any third party plug-in.
I reported these kernel panics to Apple through Bug Reporter, and through the “send report” mechanism upon restarting. Months have passed since the problem began, multiple updates to OS X 10.8 have been released, and still the kernel panics continued.
Rather than continue to wait for a solution from Apple, I opted to bypass the problem.
Replacing the Graphics Card
Thanks to a discussion on the Apple Discussion Forum, I learnt that replacing the graphics card will stop the kernel panics. One ATI 5770 graphics card can drive up to three monitors on a Mac Pro. I only have two monitors, so was pleased to feel the new card would not be immediately pushed to its limits.
Thus earlier this week, my replacement card arrived from Amazon. I had fun swapping out the two old cards for the slightly less dated graphics card.
Swapping over took about 30 minutes and required surprisingly little effort. The small manual included with the replacement provided all the instructions I needed.
Upon restarting everything worked. I have not had a kernel panic since and am starting to regain faith that I can use the computer for longer periods without being suddenly interrupted.
Update: I later re-introduced a single NVidia GT120 graphics card without problem.
Apple issued ATI Radeon HD 5770 graphics card
Two Apple NVidia GeForce GT 120 cards removed
Mac Pro empty PCI slots ready for replacement graphics card
ATI Radeon 5770 fitted inside a Mac Pro Early 2009, 4.1 model
ATI 5770 offers two DisplayPorts and one DVI port for connecting three monitors
Below is an extract of the kernel panic reports I saw. The panics were frequent enough to change my behaviour and to avoid using Safari during critical work.
Fri Mar 29 15:44:58 2013
panic(cpu 2 caller 0xffffff800a451107): "IOGMD: not wired for the IODMACommand"@/SourceCache/xnu/xnu-2050.22.13/iokit/Kernel/IOMemoryDescriptor.cpp:1424
Backtrace (CPU 2), Frame : Return Address
0xffffff81009e30f0 : 0xffffff800a01d626
0xffffff81009e3160 : 0xffffff800a451107
0xffffff81009e31f0 : 0xffffff800a44bede
0xffffff81009e32a0 : 0xffffff800a44cb0a
0xffffff81009e32c0 : 0xffffff7f8a6dea04
0xffffff81009e3330 : 0xffffff7f8a73f1c9
0xffffff81009e3380 : 0xffffff7f8a73f13b
0xffffff81009e33d0 : 0xffffff7f8a726901
0xffffff81009e3460 : 0xffffff7f8a724ad6
0xffffff81009e34b0 : 0xffffff7f8a70f764
0xffffff81009e3560 : 0xffffff7f8a73c240
0xffffff81009e3760 : 0xffffff7f8a73d983
0xffffff81009e3830 : 0xffffff7f8b7ee480
0xffffff81009e3970 : 0xffffff7f8b7edf6c
0xffffff81009e3980 : 0xffffff7f8b7e4dfe
0xffffff81009e3db0 : 0xffffff7f8b79120a
0xffffff81009e3de0 : 0xffffff7f8b7952b3
0xffffff81009e3e00 : 0xffffff7f8b11d2a4
0xffffff81009e3e20 : 0xffffff7f8b11d237
0xffffff81009e3e50 : 0xffffff7f8b7a218c
0xffffff81009e3e80 : 0xffffff7f8b7918e2
0xffffff81009e3ed0 : 0xffffff7f8b78f8a5
0xffffff81009e3ef0 : 0xffffff800a4467a8
0xffffff81009e3f30 : 0xffffff800a4452aa
0xffffff81009e3f80 : 0xffffff800a4453d9
0xffffff81009e3fb0 : 0xffffff800a0b2977
Kernel Extensions in backtrace:
BSD process name corresponding to current thread: kernel_task
Mac OS version:
Darwin Kernel Version 12.3.0: Sun Jan 6 22:37:10 PST 2013; root:xnu-2050.22.13~1/RELEASE_X86_64
Kernel UUID: [redacted]
Kernel slide: 0x0000000009e00000
Kernel text base: 0xffffff800a000000
System model name: MacPro4,1 (Mac-F221BEC8)
Amazon links on this page help support running The Work Life.