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

Yes - exactly the same as yourself. As you may have read I had actually ordered a new GPU for my iMac 8,1 (2008) having been stuck on 10.6.2 for well over a year. I knew the kext fix was good on 10.6.7 to which I upgraded to initially, but then I found that iLife11 would not load.

I was forced to go 10.6.8 but I had read that the kext fix would not work on this release :-(

However, some of the very helpful guys here convinced me to go for it on 10.6.8, so long as I ran in 64 bit mode. I took it slowly, I switched my machine to 64 bit mode, then changed the default boot mode (for 64 bit) and ran it there for a while. Did a couple of reboots to ensure was good. ps. I had taken a full backup prior to this.

I used the kext helper which worked cleanly within a few seconds, but the reboot did hang which concerned me a little. I needed to kill the kext helper from the Unix prompt before the system rebooted. After experiencing a hang my heart was in my mouth for a few seconds, but was relived to see it boot properly.

So far (24 hours in) no hangs, so I will cancel the GPU I ordered, but will have to remember to do the kext fix when I go to Lion.

I have Lion on a machine less than ayear old and it is completely frozen. No response to mouse or pad. Argh!!!

Apple Store couldn't recreate my problem and tried pointing at Vmware which was installed on my system. I explained that Vmware was definitely not the issue - the lock ups existed before I installed Vmware.

They replaced the GPU and logic board... took it home yesterday and lockups continued.

Definitely software related unless they didn't really do the replacement... I'm blown away here.

Time machine was running during last lock up. My instinct was to disable time machine and see if lock ups continue... but I think I've done that before. I feel like I'm running around in circles here.

Thanks are due to Krzysiu Turek, who deserves the Nobel Peace Prize for posting his kext-based solution.

First of all I thought VMware Fusion was the issue of the crashes of my iMac. Thus, I reinstalled my iMac without VMware and with Parallels. But the same crashes had happened. Next, I reinstalled my iMac without both of them. Anyway I've had the crashes. Only kext helped.

I've got the Apple Protection but in my opinion it's not the correct solution to use an other GPU as I've had originally bought. In my opinion it's an software bug and not a hardware failure and I demand a software solution of Apple...

Has anyone tested the fix with lion 10.7.4??? Any kernel panics?

Yes - it is a software bug alright, my machine (fingers crossed) has been stable since I upgraded to 10.6.8. (64 bit) with the Kext fix.

I am so pleased I did not waste £134 of my money on a new GPU which at the time I thought would fix the problem but it appears that it is not certain to.

Again I applaud Krzysiu Turek for the clever Kext fix which is a get out of jail fix if ever I saw one! Did not know there was a 10.7.4 release out now (then again I am not on Lion) so yes - it will be interesting to see if the Kext fix works on that.

Goodness knows what we do when eventually (surely) the 10.6.2 drivers fail to work with new release of Lion or Mountain Lion.

Are any of you seeing artifacts/pixellation like the ones described in this thread?

https://discussions.apple.com/thread/3938355?start=0&tstart=0

Hi. upgraded to 10.7.4 yesterday. this is an imac7,1 with ati2400.

right now i am running the upgraded kexts, and for the first time i was able

to lauch a 3d-accelerated game on this imac (heroes V).

i tried it many times, it hung always on the same spot, always the same way, with the good old GPU debug in system.log. even if used with the 10.6.2 kexts.

now it's ok. dunno, maybe a coincidence, but until now had no freezes. i'll keep you posted.

Those of you running Lion and NVIDIA GT 120 or GT 130 GPUs, and having crashes and pixellation issues, try running Lion in 32-bit mode (start up holding 3 and 2) and see if they continue. I just did this tonight and have been colored-pixel-free for about 5 hours now, no crashes, mosaics, or any other graphics anomalies.

If it works, come back to report so others can learn about it!

I have the NVIDIA GT130 and suffered all of the same problems. I also tried running in 32 bit mode but the symtoms continued. I finally replaced the GPU with a revised GT 130

card under Apple care. I have now been running absolutely trouble free for 2 months. The technician told me my card was overheating due to Lion maxing out the resources of the card. Fan Control for Mac ( free download ) helped to cool it down, but not enough. Kext fixes were not available for this card. ( No driver download support.)

Yes logic would suggest a graphics card problem causing screen image faults. Imacs just don't have the cooling space inside for the cards that Powermacs have, and if they are sitting on a desktop with free air all around them that's about as much as you can do apart from possibly taking the back off the clean away any accumulated dust. I've got an ageing 24' 2006 with intermittent screen image freezing problems caused by the card heating up and I'm trying to keep it cool until the new iMacs come out hopefully next month. I just hope they don't run hooter than the card can cope with!

no luck. although heroesV runs w/o problems, watching a youtube video brings the gpu to it's knees.

i'm about to try the 10.6.2 drivers.

btw. it's an alu imac7,1 with ATI HD2400

Kext fix works on my 8.1 imac (radeon 2600pro) with Lion 10.7.4.

I also have an 8,1 imac with a Radeon HD 2600 pro, but the kext solution hasn't solved the hangs for me on 10.7.4. Like others, I can pretty easily trigger them when downloading multiple things via iTunes.

If it does work for you, it would be helpful to me (and hopefully others) if you could post some additional info from the System Information utility (System Profiler in 10.6).

Go to Software -> Extensions and scroll down to the ATI extensions. After moving the 10.6.2 kexts into place, I have:

ATI2600Controller:

Version: 1.6.6

Last Modified: 8/3/09 2:06 AM

Get Info String: ATI2600Controller 1.6.6.25 (7429)

Kind: Intel

Architectures: i386, x86_64

64-Bit (Intel): Yes

Location: /System/Library/Extensions/ATI2600Controller.kext

Kext Version: 6.0.6

Load Address: 0xffffff7f81711000

Valid: Yes

Authentic: Yes

Dependencies: Satisfied

ATIFramebuffer:

Version: 1.6.6

Last Modified: 8/3/09 2:04 AM

Get Info String: ATIFramebuffer 1.6.6.25 (7429)

Kind: Intel

Architectures: i386, x86_64

64-Bit (Intel): Yes

Location: /System/Library/Extensions/ATIFramebuffer.kext

Kext Version: 6.0.6

Load Address: 0xffffff7f816fa000

Valid: Yes

Authentic: Yes

Dependencies: Satisfied

ATIRadeonX2000:

Version: 7.18.18

Last Modified: 6/24/11 2:14 AM

Get Info String: ATIRadeonX2000 7.18.18 11019

Kind: Intel

Architectures: i386, x86_64

64-Bit (Intel): Yes

Location: /System/Library/Extensions/ATIRadeonX2000.kext

Kext Version: 7.1.8

Load Address: 0xffffff7f8140c000

Valid: Yes

Authentic: Yes

Dependencies: Satisfied

ATISupport:

Version: 1.6.6

Last Modified: 8/3/09 2:05 AM

Get Info String: ATISupport 1.6.6.25 (7429)

Kind: Intel

Architectures: i386, x86_64

64-Bit (Intel): Yes

Location: /System/Library/Extensions/ATISupport.kext

Kext Version: 6.0.6

Load Address: 0xffffff7f813c7000

Valid: Yes

Authentic: Yes

Dependencies: Satisfied

Note that ATIRadeonX2000 is the Lion version, and the other three are the 10.6.2 versions. Maybe that's the problem? If I copy over the X2000 kext as well, the machine won't boot. What do things look like for others?

BTW, my Hardware -> Graphics/Displays section is:

ATI Radeon HD 2600 Pro:

Chipset Model: ATI Radeon HD 2600 Pro

Type: GPU

Bus: PCIe

PCIe Lane Width: x16

VRAM (Total): 256 MB

Vendor: ATI (0x1002)

Device ID: 0x9583

Revision ID: 0x0000

ROM Revision: 113-B2250L-259

EFI Driver Version: 01.00.259

Displays:

iMac:

Resolution: 1680 x 1050

Pixel Depth: 32-Bit Color (ARGB8888)

Main Display: Yes

Mirror: Off

Online: Yes

Built-In: Yes

Thanks,

Joe