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

Any progress on this? I haven't been able to upgrade past 10.6.2 so I wasn't able to install FaceTime for Mac today. My 2008 iMac with a ATI Radeon HD 2600 Pro freezes with either a white screen or slight blue banding/striping as many have described. You think it might be a hardware issue? It sounds like a software bug but I'm out of options.

I have a 2008 iMac (iMac 7,1) and I've been holding off with 10.6.4 as it had been freezing (going to a black screen) with me in the past.

Yesterday I installed 10.6.4 (yet again) to use the FaceTime beta. Following the advice of someone else on this thread, I used smcFanControl to speed up my iMac's fans by 50%. My system has been stable since. I've had it running for 12 hours+ when previously it wouldn't run for more than 2 hours without a freeze.

Looks like all Apple will have to do in a future release is set a new baseline fan speed for the graphics card, I think.

As a side note: I looked into possible graphics driver updates being the root cause - They're not the root cause - The drivers in 10.6.4 are the same version as 10.6.2. Therefore I'm starting to suspect it's purely a thermal management issue.

I'll post again in a couple of days once I've thrashed my system a bit.

I have this issue on my iMac 8,1 (8800gs). It started with a lock up in Windows 7 playing Civ 5. After reboot, Windows would turn completely white. Booting in to OS X would result in the screen turning completely black, or purple in some cases, even booting from the Snow Leopard CD to run diags. I do not think these issues are at all related to software.

I have to wait for an hour or so for the hardware to cool off. I've cleaned out the air intake and output areas to make sure air was flowing freely. smcFanControl is kicked up to 3000rpm and i reguolarly see 180 deg. on CPU/GPU after minor use.

I'm fortunate enough that if the iMac survives the login process, it will perform fine unless I launch something graphic intensive, then it will freeze up. I am saving up for the 8800gs adapter to replace it myself since Apple wants to charge outrageous fees and the use of their special tools (ie. suction cup and T8 Torx driver).

I would recommend you keep an eye on yoru temps constantly in Windows and OS X so permanent damage does not occur. HDDs will fail with excessive heat too so keep that in mind.

Good luck.

Guys, I'm sick to this problems. Apple can't find a cure to this YET??? I bet it's an incompatibility issues with the videocard.

I'm ready to install iLife11 but I can't because I'm still using 10.6... iLife11 requires 10.6.3 or later.

10.6.3 killed my hard drive few months ago. and here i am again checking if 10.6.4 did some trick, STILL!!! Apple .... PLEASE address this issue. give this a priority... stop doing anything new until this issue's resolve. No one will buy iLife11 then.

in fairness, i know apple is sick to this too.

Latest from me is that I still get the odd freeze/crash, with kernel at 64bit. It does look like the GPU is the problem and it may be heat related, but so very strange that this only occurs after 10.6.2 (which I back installed successfully for several weeks, only to try 10.6.4 and the graphics update)
Have done the maintenance stuff with OnyX and cleared out any suspect fonts with Font Book. Now have smcFanControl winding up the fans for the CPU and Optical Drive (around 1300+ rpm) and monitoring GPU temperatures in the iStatPro widget. It now crashes about once every two to four days.
What does annoy is that it is very difficult to report issues directly to Apple unless the OS "sees" the crash and kindly asks you to forward details on the next reboot - I think I managed it once or twice, but not sure if I managed it under 10.6.4. These crashes seem fundamental as the OS doesn't suspect a thing!
However, I do have crash logs on the Console and it reports a GPU crash via the kernel - a small extract is:
Fri 22 Oct 10 16:31:19 pm kernel 0xc0026900
Fri 22 Oct 10 16:31:19 pm kernel 0x0000000c
Fri 22 Oct 10 16:31:19 pm kernel 0x00000000
Fri 22 Oct 10 16:31:19 pm kernel 0x20002000
Fri 22 Oct 10 16:31:19 pm kernel 0xc0036900
Fri 22 Oct 10 16:31:19 pm kernel 0x00000080
Fri 22 Oct 10 16:31:19 pm kernel 0x00000000
Fri 22 Oct 10 16:31:19 pm kernel ** GPU Debug Info End **
Fri 22 Oct 10 16:31:30 pm kernel ** Device in slot: SLOT--1 **
Fri 22 Oct 10 16:31:30 pm kernel ** GPU Debug Info Start **
Fri 22 Oct 10 16:31:30 pm kernel 0x00009583
Fri 22 Oct 10 16:31:30 pm kernel 0x000000d6
Fri 22 Oct 10 16:31:30 pm kernel 0x00000001
Fri 22 Oct 10 16:31:30 pm kernel 0x00000018
Fri 22 Oct 10 16:31:30 pm kernel 0x00009052

...but the iMac never recovers or locks. I could send the whole lot if anyone really wants it. I did attach it to a report problems with Safari... Anyone know how to report properly to Apple for the OS and iMac???

I can confirm that after running my iMac 7,1 on 10.6.4 with increased fans speeds for about 4 days that it's stable, even whilst running GPU heavy games.

So as a general note: Try speeding up your fans using smcFanControl and see if that helps your stability issues.

I had the same experience as the last post - smc fan control saved the day for me too! This link may be helpful, despite the different problems listed:

http://appletoolbox.com/2010/08/problems-after-snow-leopard-graphics-update-1-0/

cheers!

Already done all, but froze again.

Just happened again. Here my picture.

http://img175.imageshack.us/img175/803/img0050vu.jpg

@ vexbit
Can I get a screenshot of the smcFanControl preference window?

Sorry, I don't have access to the computer anymore. I was updating a friend's computer. He's been using it for several days with no issues. All I can say is that I moved the 3 sliders in the preferences about halfway. It should be noted that we are talking about OSX.6.4 in this case.

Unbelievable.
vexbit. I really appreciate you. You were right. freeze problems were due to thermal issues.
Until now (about 4 days), I haven't seen a freezing screen.
Thank you again.

eeemin wrote:
Just happened again. Here my picture.

http://img175.imageshack.us/img175/803/img0050vu.jpg

This is pretty much what I see on a regular basis. iMac 8,1 24" ATI HD 2600 Pro.

Also only started after 10.6.3. What's weird is that it doesn't seem to be related to running heavy graphics stuff, but I know that certain "graphical" things have caused the freeze to appear to happen more often.

I usually use Ctrl+Zoom and sometimes it seems that during use of that, the mac freezes. Or if I use the Dock's Stacks, that also I believe has happened a couple times right when opening a stack.

Is there a way to test the video memory on these machines? Something that will touch every bit of memory to see if it locks up at some particular register? Any other ideas?

Guys, *MacOS X 10.6.5* came out today, can someone please report if it fixed the freezing problem after we updated to 10.6.3? i too reverted back to 10.6.2 because i couldnt stand the freezing, and i also purchased ilife 2011 and i cant install it as it requires 10.6.3 or above, i also cant use Facetime which i really want as it requires 10.6.3 too, i also wont be able to use itunes 10.1 i think.