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Late 2007 iMac 20" Freezes completely random.
- Thread starter Naad
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IIRC, at the time the freeze was put down primarily to a problem with one of the suppliers of VRAM to the video card. The firmware patch that Apple released was said to have played with the timings of the VRAM. My son's iMac had a logic board/GPU switch after one month and never looked back. I would not have thought, however, that this cause was one that could lie dormant for several years before appearing. It was usually found right out of the box.
The firmware update was only for one subset of the cards. The iMacs that are currently effected by this problem are ones that are not eligible for the update. This problem is a software bug caused by one of the ATI kexts in Mac OS 10.6.3/.7 (depending on the card) through 10.7.5 and 10.8.2. It does not effect Boot Camp or any other version of Leopard. It is not caused by overheating or graphically intense operations.
I see. I never upgraded them beyond Leopard and have sold them on. Glad I did now. The previous bug didn't need anything intense either. It would freeze up on a cold boot at the desktop. Same symptoms, different issue.
Just sayin'...
For those of you with the issue on the ATI card being discussed - I know how frustrating this is, believe me. I had a similar issue on a later model iMac with a different graphics card, and ended up having that GPU replaced...fortunately under warranty. So I've been dealing with this kind of thing on multiple machines. But here's the thing...
For machines with the ATI card, the kext replacement is really, really easy. It's so easy that I've continued updating my machine (currently at 10.7.5), and just do a quick kext replacement when the update finishes (using the 10.6.2 kext files)...takes all of 30 seconds.
So, if you haven't tried the kext fix yet - go for it. You'll wish you had done it long ago.
ps: There are numerous kext utilities. I use Kext Wizard. Drag and drop the three kext files into the dialog, press the Install button, and bam! Done.
For those of you with the issue on the ATI card being discussed - I know how frustrating this is, believe me. I had a similar issue on a later model iMac with a different graphics card, and ended up having that GPU replaced...fortunately under warranty. So I've been dealing with this kind of thing on multiple machines. But here's the thing...
For machines with the ATI card, the kext replacement is really, really easy. It's so easy that I've continued updating my machine (currently at 10.7.5), and just do a quick kext replacement when the update finishes (using the 10.6.2 kext files)...takes all of 30 seconds.
So, if you haven't tried the kext fix yet - go for it. You'll wish you had done it long ago.
ps: There are numerous kext utilities. I use Kext Wizard. Drag and drop the three kext files into the dialog, press the Install button, and bam! Done.
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Also, as has been mentioned, the 7,1 system with 10.6.8 will not work with the kext fix (either from 10.6.6, as Intell has had good fortune with, or 10.6.2, as this recommends and I have had success with); you have to either keep it at 10.6.7 or go to 10.7.x or 10.8.x (which both currently accept the kext fix).
Should really get some sort of definitive post/sticky up for this issue, but the previous link in this post is close enough.
Should really get some sort of definitive post/sticky up for this issue, but the previous link in this post is close enough.
7,1 iMacs with 10.6.8 work fine with 10.6.6 or 10.6.2 extensions. My own iMac is running 10.6.8 with 10.6.6 ATI kexts.
Too early for that sticky then! 
I consistently couldn't get my (family member's) 7,1 ATI 2400 to boot using .2 or .6 kexts when running 10.6.8, but on 10.6.7, and eventually on 10.7.5 which she is content with semi-permanently, it's been smooth sailing. I found several other people with similar issues who had come to a similar conclusion that (to refer to an older post I made):
It's obviously quite a convoluted issue, even though this thread and the one linked above have nailed it down pretty well.
I consistently couldn't get my (family member's) 7,1 ATI 2400 to boot using .2 or .6 kexts when running 10.6.8, but on 10.6.7, and eventually on 10.7.5 which she is content with semi-permanently, it's been smooth sailing. I found several other people with similar issues who had come to a similar conclusion that (to refer to an older post I made):
It's obviously quite a convoluted issue, even though this thread and the one linked above have nailed it down pretty well.
what do you suggest to troubleshoot those issues? I haven't attempted this since it crashed my imac a few months ago, and I followed the directions then.
Well I'm going in, I've had enough since upgraded to 10.7 from 10.5 (and not researching issues...) earlier this year. I have a 7,1 iMac and the 2400 card the same as the model in question discussed in this thread.
Wish me luck!
how long
many thanks guys.....
how long have you been using 10.7.5?
have you try with game that will get your gpu tired/hotter.. like cod, counterstrike, etc..
this special imac perhaps need more attentions.
i am using with kext 10.6.1 now and my system is 10.6.8..
i am using smc and hdd fan control at full speed three of them, odd and cpu control with smc while hdd with hdd fan control, because the room temp is not that cold. i set hdd to 45 deg of C with minimum 40. (keep below 50)
i use odd and cpu at full speed to help keeping the imac body cooler, but still in the left side which is the source of heat (heat sink of cpu, gpu and psu was on the top of left) still a little bit hot.
i tested with that game and still quite good.
and i will go little bit further by trying with:
reapply the thermal paste on gpu ( it's been 5 years, perhaps the thermal paste was weak)
add something cooler stuff on the body, like attaching peltier on the body(easier) or above the heat sink(harder way), or put extra fans to help air flow faster.
you guys, intell and other were right about kext stuff. but still imac no matter years of made and other electronics stuff will face of with heat.
low heat, faster and longer life will be
many thanks guys.....
how long have you been using 10.7.5?
have you try with game that will get your gpu tired/hotter.. like cod, counterstrike, etc..
this special imac perhaps need more attentions
.i am using with kext 10.6.1 now and my system is 10.6.8..
i am using smc and hdd fan control at full speed three of them, odd and cpu control with smc while hdd with hdd fan control, because the room temp is not that cold. i set hdd to 45 deg of C with minimum 40. (keep below 50)
i use odd and cpu at full speed to help keeping the imac body cooler, but still in the left side which is the source of heat (heat sink of cpu, gpu and psu was on the top of left) still a little bit hot.
i tested with that game and still quite good.
and i will go little bit further by trying with
:reapply the thermal paste on gpu ( it's been 5 years, perhaps the thermal paste was weak)
add something cooler stuff on the body, like attaching peltier on the body(easier) or above the heat sink(harder way), or put extra fans to help air flow faster.
you guys, intell and other were right about kext stuff. but still imac no matter years of made and other electronics stuff will face of with heat.
low heat, faster and longer life will be
many thanks guys.....
how long have you been using 10.7.5?
have you try with game that will get your gpu tired/hotter.. like cod, counterstrike, etc..
this special imac perhaps need more attentions
i am using with kext 10.6.1 now and my system is 10.6.8..
i am using smc and hdd fan control at full speed three of them, odd and cpu control with smc while hdd with hdd fan control, because the room temp is not that cold. i set hdd to 45 deg of C with minimum 40. (keep below 50)
i use odd and cpu at full speed to help keeping the imac body cooler, but still in the left side which is the source of heat (heat sink of cpu, gpu and psu was on the top of left) still a little bit hot.
i tested with that game and still quite good.
and i will go little bit further by trying with
reapply the thermal paste on gpu ( it's been 5 years, perhaps the thermal paste was weak)
add something cooler stuff on the body, like attaching peltier on the body(easier) or above the heat sink(harder way), or put extra fans to help air flow faster.
you guys, intell and other were right about kext stuff. but still imac no matter years of made and other electronics stuff will face of with heat.
low heat, faster and longer life will be
smc set to default and 30 minutes later it freeze
. the temp become 56 C. hdd fan control read 45CSame problem in my iMac 7,1 with ATI 2600 Pro
I never noticed this problem until I upgraded to Mountain Lion... It never appeared before ~10.8 for me. I've read so many threads, but I just want to be sure... if I install 10.6.2 kext files on my 10.8.2 installation, this should fix my problem?
I've found the ktext files available for download here, so I shouldn't need to go through the long process of downgrading just to get the files:
https://discussions.apple.com/thread/2384136?start=345&tstart=0
Thanks for your dedication to this thread, Intell... it's been really helpful.
I never noticed this problem until I upgraded to Mountain Lion... It never appeared before ~10.8 for me. I've read so many threads, but I just want to be sure... if I install 10.6.2 kext files on my 10.8.2 installation, this should fix my problem?
I've found the ktext files available for download here, so I shouldn't need to go through the long process of downgrading just to get the files:
https://discussions.apple.com/thread/2384136?start=345&tstart=0
Thanks for your dedication to this thread, Intell... it's been really helpful.
Yea well, I like my iMac and I want to keep it around for a few more years. You can try either the 10.6.6 or the 10.6.2 ATI extensions. I suggest the 10.6.6 first. If the problem persists, go with the 10.6.2 extensions.
Hi Intel, I'm one of them that tried to use 10.6.6 kext with 10.6.8 and got panic at start up. Mine is 7,1 so I can't boot in 64-bit. You mentioned about incorrect permissions or wrong next version. Could you explain a bit more about what are the right permissions or right next version?
Thank you so much for your contribution here.
Hi all i'm glad i found this thread cause im having similar problem (early 2009 Imac with Ati radeon 4850) i have read most of the posts and wanted to try the kext replacement but the ones i downloaded from here (http://blog.krzysztof-turek.com/apple-imac-8-1-freeze-problem-solution-en/) don't mention an 4850 card (only a 4800) should i try with the 4800 or preferably not !??
thanks for any help....
thanks for any help....
thanks intell for the heads up.... despite it doesn't help me solve my freezing issues (that look oddly similar to most people posts here: display is frozen, mouse moves, keyboard has no reaction)... actually i installed this fan control thingee and pushed the fans to around 2500 rpm... let's have a look if that works.... anyway i was going for a clean install which might help too.
I have the mid2007 iMac with ATI2400 video card. I can't pinpoint when the freezing started, but now at 10.7.5 it is ridiculous. It will freeze with various clicks or menu selections in many stock programs.
I came across that Polish site mentioned a few posts earlier. I installed the drivers from 10.6.2 The freezing stopped completely. Unfortunately the video performance suffered greatly in some areas. For instance dragging iPhoto around the screen would show blocky artifacts, switching users would stutter from one user to another, Launchpad would launch so slowly you could see the various animation stages. I could live with all that, until I discovered that Pages and Numbers (iWork09) exhibit a blank white page. I can open existing files and confirm that data is there, but you can't see anything on the page. That's a deal breaker for me, those programs are a necessity.
I'm going to try drivers later than 10.6.2 and see if I can find something that alleviates the freeze, yet still lets me work.
I came across that Polish site mentioned a few posts earlier. I installed the drivers from 10.6.2 The freezing stopped completely. Unfortunately the video performance suffered greatly in some areas. For instance dragging iPhoto around the screen would show blocky artifacts, switching users would stutter from one user to another, Launchpad would launch so slowly you could see the various animation stages. I could live with all that, until I discovered that Pages and Numbers (iWork09) exhibit a blank white page. I can open existing files and confirm that data is there, but you can't see anything on the page. That's a deal breaker for me, those programs are a necessity.
I'm going to try drivers later than 10.6.2 and see if I can find something that alleviates the freeze, yet still lets me work.
Try using the 10.6.6 drivers. They're a newer version than that 10.6.2 ones and solve lots of freezing problems. Only a few freezes that cannot be fixed by the 10.6.6 ones need the 10.6.2 drivers. But people incorrectly suggest the 10.6.2 ones first because they fix the most freezes, but come with the most negative side effects.
Thanks. What's confusing is that I just went through a bunch of TM backups from 2012 and all of the ATI drivers I have are are v1.6.36.10 (probably from 10.6.8)
The ones I downloaded that were claimed to be from SL10.6.2 are v1.6.6
Odd numbering scheme where the newer ones are a lower number?
The only other ones I found were the earlier Lion v7.18.18 as opposed to the v7.32.12 which are in Lion 10.7.5
=======UPDATE=====
I installed the 1.6.36.10 drivers and the video performance is somewhat back to normal. Some missing features - Slideshows don't work in iPhoto 11, fast user switching doesn't have the rotating cube effect, no deal breakers yet.
I will see about the freezing situation and report back.
P.S. if anyone has can send me earlier versions of SL drivers (the fabled 10.6.6. drivers, v??) I'm willing to try them out.
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