Q: 24" iMac Screen Freezes since 10.6.3 update - pls help!

A short Update from me.

As written at the 21.Sept. the GPU was changed by Apple (read about the hard struggle at this posting). It is the same GPU but with a changed revision. Lucky enough - I have had an apple care for this machine which is always a good option.

Until now (since more than 6 month) there were no freezes any longer.

So, if you are not willing to manually update the driver with the old 10.6.2. Version - changing the GPU seems to be the only way getting out of this mess.

Congrats Michael!! That's definitely good news! Could you please write the specs of the new video card and the specs of your iMac?

do we want to try this one to dump the fw of a good gpu and flash the bad one.

http://www.groths.org/?page_id=108

Specs of the Mac and the changed GPU:

iMac 8.1 24"

Intel Core Duo

2.8GHz

SMC-Version 1.30f1

Message was edited by: michaeljaekel

michaeljaekel, thanks for the update--it's good to confirm that a hardware change can solve the problem.  Interestingly, my iMac  and its GPU are exactly the same as yours, according the the numbers you posted -- same Device ID, Revision ID, ROM Revision, EFI Driver Version, etc. -- yet I got screen freezes often until I went with the 10.6.2. "kext fix" (which works 7 months now for me).

So if your new GPU is a different revision than the original, it doesn't seem to show in the System Profiler.  Wondering what made you believe it was a different revision?  Info from the tech?  Looking at the circuit board?  Curious to know.

That's what my apple service center man told me, too. But he is shure that the new GPU is another revision than the originaly build in, even if the about mac doesn't show it....

And at least: its running since the change!

Oh great, so those without the Apple Care now have to spend hundreds of dollars fix this common issue?

That really *****...

The hack fix going back to the 10.6.2 drivers for my 8,1 with the ATI2600 card has been working for a week now with no crashes.  I was getting two or three per day.

Not that difficult if you follow the guide.

Good outcome and an end to the only real frustration I've had since swapping from Windoze.

Well I had a good two - three weeks running.  Now my iMac is crashing constantly.

Odd though, since I'm no longer getting the lines when it crashes.  Sometimes only my mouse can move.  Sometimes the whole screen freezes all together.

I'm going back to making my own computer and using Windows.  Later Apple.

Well, after the latest OS update, the freezes reoccured.  Sure enough, the three kext files were updated.  I just replaced them again with the 10.6.2 versions, and am back to a stable MAC.    I like the fact that a newer GPU also seems to fix the problem, but I've been off Apple Care for sometime, and don't feel like putting more money into this Mac.  I'dd ride this temp fix out as long as possible.... then maybe it will be time for a new Mac!

You're right. The kext fixes worked for me, but I also got a new GPU (ATI 2600 Pro) under Apple Care 9 months ago and haven't had a problem since then even with the new kexts. Yippee! The cost would have been $179 for the GPU otherwise.

24" Mac.  3.06 GHz Core 2 Duo.  I just had my GPU replaced (NVIDEA GeForce GT 130) under Apple Care and I have had no stability issues since. I asked the service tech if it was a revised card as it was the same model as I previously had. He was not sure. My computer seems to be faster and I am able to multi task and run any programs flawlessly. The pixilating and cursor freezing is gone at last. Prior to my replacing the GPU, I downloaded for free,' Fan Control for Mac'. It enabled me to bump up my cooling fan speed which helped a lot but problems persisted. The Tech did tell me my computer had over heating issues. He was not sure if the GPU or Logic board were the problem. So far it looks as though it was the GPU after all. Only time will tell but so far so good. Apple is getting blamed for all this when it might be the manufacturer of the Graphics cards.

If replacing the GPU is the only way out, I am tempted to buy a new one GPU, sadly at my own expense. I have been running 10.6.2 now for well over a year without issue. I have not been tempted to upgrade since having endured countless crashes/freezes when going up to 10.6.6 I think it was.

The kext fix is a fantastic workaround, but it is not for me.

I assume I would book an appointment at the Genius bar and bring my iMAC along with me? I would want to check with them first though that they can do the job there and then, not easy for me to get to my local store.

So frustrating though!

I'm trying to decide whether it's worth my while to try and use my AppleCare to replace the GPU on my iMac 8,1 running under OS X 10.6.8. Since I did the kext fix about six months ago, I haven't had any freezes. Prior to that, I had numerous random freezes which I reported to Apple with no resolution.

I'm concerned about whether the kext fix will continue to work going forward especially if I choose to upgrade to Lion or Mountain Lion. I've got to make the decision soon because my AppleCare expires at the end of this month but I don't want to waste my time if I'm just going to get shot down by Apple.

Isn't your apple care over now?  Your iMac is first quarter 2008, it's first quarter 2012 now, that's 4 years ago.  Isn't apple care only for 3 years?