Model A1224 / Mid 2007 and Early 2008 / 2, 2.4, or 2.66 GHz Core 2 Duo processor

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Random kernel panics and slow downs

Hello, and sorry for the lengthy post (I'm trying to be as thorough as possible)!

My buddy has this early 2008 iMac that's been giving him trouble and since he doesn't have much cash to play with I offered to take a look at it for him.

Basically it starts slowing down at a random point and then, about 30-60 seconds later it reboots without warning. Almost as if someone pulled the plug for a split second.

I booted from MemTest86 5.1 and all the RAM (3Gb) checked out fine. As did the HDD in Disk Utility. I did a clean install of Mavericks and the problem persists.

I don't think this is relevant but, just in case... The 250GB HDD was oddly partitioned. 170GB for OSX and the rest unallocated. I erased everything before installing Mavericks so now it's a whole 250GB partition.

The crashes occur more frequently when I'm trying to do maintenance on the computer. It is impossible to install any software updates so we're stuck on OS version that came on the dmg I used. Also any diagnostics processes I launch usually result in a crash. Web browsing can be done for at least 30 minutes without an issue. It even crashed once when I attempted to boot from the Mavericks DVD, but the 2nd attempt went fine.

Holding down 'D' on the keyboard during startup does nothing.

When I look through the crash logs I see that the source of the crash is always the same: The processor became unresponsive. But the reason for it's unresponsiveness differs from one crash to the other. I'm thinking this could be fixed by replacing the CPU, but I've also heard of the GPU causing similar problems.

Overheating seems unlikely since it boots up fine immediately after each crash. And the time between crashes doesn't appear to relate to hot or cold boots.

I haven't attempted to decipher crash logs before so a second opinion would be greatly appreciated! :)

I'm going to post some of the crash reports as a reply to this question to prevent being blocked by the automated spam filter

Answered! View the answer I have this problem too

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Most of the crash logs say something like this:

panic(cpu 1 caller 0xffffff80010c030b): "TLB invalidation IPI timeout: " "CPU(s) failed to respond to interrupts, unresponsive CPU bitmap: 0x1, NMIPI acks: orig: 0x0, now: 0x1"@/SourceCache/xnu/xnu-2422.100.13/osfmk/x86_64/pmap.c:2612

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BSD process name corresponding to current thread: mdworker

-The current thread varies, sometimes the mdworker, sometimes a kernel task and sometimes core audio....

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Apple computer, especially iMacs in my xp hate odd amount of ram. try booting up with just 2gb of ram

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When u get a kernel panic, it almost always means ram

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So it could be the odd number of ram gbs ora bad ram stick. u can't do anything heavy with two gbs of ram though so it might crash. if that doesn't work, then try it in the other ram slot. u might want to get new ram as a last test, if all else fails.

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Not true, kernel panics usually indicate GPU issues (more likely in this case, since GPU failures are common in iMacs) and sometimes CPU. I have never come across one kernel panicking due to RAM, since it will usually not boot up in this case (beeping instead)

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Sounds like it could be an issue with the WiFi, since you are having difficulty finding any networks. WiFi cards which have gone bad can cause both an issue with finding networks and kernel panicking. It could be the GPU going bad instead, which can cause issues like this too, but the fact that WiFi is not working could indicate this is the cause.

First, try booting from another hard drive (external, by USB), to rule out the hard drive or software causing an issue. If the issue still occurs, I would order an Airport card and try that out, checking out the surrounding area on the logic board, to make sure nothing looks burnt or scorched. If you still have the same issue, try a new GPU, but it is probably not worth repairing in this case (expensive, difficult to find and will likely fail again, since pulled from a used unit).

I think it might be best on this occasion to try the Airport card, give the logic board a quick inspection, and if it still has the same issue, write it off unfortunately, due to the age, cost of repair and risk of the issue happening again.

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Would removing the Airport card without replacing it fix the problem? That is, if the Airport card is the culprit.

Thanks for the help! :D

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@alliat yes, it won't kernel panic if it doesn't recognise the Airport card

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Oh, WiFi is a small price to pay to get rid of the panics since a LAN cable fixes it so easily. Oddly enough this may be exactly the same problem I'm facing on my Nintendo 3DS XL which crashes always and only when WiFi is on.

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