Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

iMac Freezing

Hi there,

I have one of the older (first gen 24" intel) iMacs. Its been fine until recently.

However, it now occasionally locks up (once 3 times in a day) and over the past week I'd say its occurred about 7-10 times.. The freezing seems to come about shortly after I notice some gfx glitches.

The problem seems to arise after running a movie or flash movie.

I had noticed a similar issue before whilst playing World of Warcraft, a problem solved by running smc fan control and setting the fans to run at a high rpm. I suspect the problem is gfx kernel panic related. However, I dont wish to run the fans at full pelt all the time as it will shorten their lifespan and its hardly a decent solution.

Can anyone offer any help?

Thanks..

iMac 24", Mac OS X (10.5.2)

Posted on Mar 31, 2008 7:35 PM

Reply
Question marked as Best reply

Posted on Apr 5, 2008 9:25 PM

Hi please do this:

http://docs.info.apple.com/article.html?artnum=303446

Also try this:

http://docs.info.apple.com/article.html?artnum=2238

Thanks
562 replies

Apr 10, 2008 9:40 PM in response to dynamostia

My iMac started having the similar problems when I upgraded from 10.4 to 10.5. I have been hoping that a system or firmware update would solve it, but so far no. The problem starts, seemingly randomly, with the appearance of a horizontal line of messed-up pixels. They might be in an application window or on the desktop, they might disappear if the window is refreshed or maybe not. Once the bad pixels appear, it is only a matter of time before the system freezes and must be switched off. The freezing also seems to appear at random times. No crash report is created when I reboot. It has happened so often that I turned on journaling so the computer would reboot faster.

What has not worked: system or firmware updates, resetting the PRAM, resetting the SMC, replacing the RAM, turning off TimeMachine and iMac syncs, running maintenance with Cocktail, rebuilding the directory with DiskWarrior.

I had high hopes on the recent 1.3 firmware update but the updater said my machine was already up-to-date (Boot ROM Version IM61.0093.B07).

It's like I'm back in the System 7 era.

Apr 12, 2008 8:41 AM in response to dynamostia

I have what sounds like the same freezing problem, also on a first generation 24" intel iMac. I find no relation to the fan, but the symptoms are the same.

1. A graphics anomaly appears on the screen, either a horizontal blue line or a wedge-shaped blur of screen material.

2. 5-15 minutes later, the iMac freezes, in the following sense. My (bluetooth) mouse can still move the pointer around the screen, and if iTunes is playing music, it keeps playing. But no keyboard input is possible, mouse clicks have no effect, and running programs are frozen.

This set of problems started with the recent 10.5.2 update, though the graphics anomalies on their own appeared when I first installed Leopard. I've checked RAM, done all sorts of usual procedures (permissions, deleting caches, etc.) -- nothing helps and nothing comes up as an error.

The freezing happens reliably after anything from 30 minutes to a few hours of use, and is becoming an enormous problem.

Apr 12, 2008 9:54 AM in response to dynamostia

There is another discussion on this same topic

http://discussions.apple.com/thread.jspa?messageID=6513194

where one respondent said that when he reboots in safe mode the problem disappears, so I wonder if it might have to do with some non-Apple framework or background application.

I checked System Profiler on my machine and here some Extensions that are non-Apple: CiscoVPN (2.0.1), Soundflower.

Among the Frameworks are: cisco-vpnclient, YahooSync.

Preference Panes: A Better Finder, Adobe Version Cue CS3, Flip4Mac WMV, iStat menus, MySQL. Perian.

Startup items: CiscoVPN, MySQLCOM.

Also I have FileMaker Server 9 and DNSUpdate 2.8 running in the background.

Do we all have the NVIDIA GeForce 7300 GT video card? The weird monitor issues make that a suspect.

I hope we can fix this before my wife makes me switch to a PC. I've been running Macs since the Plus.

Apr 12, 2008 8:51 PM in response to dynamostia

i have been having this problem for 2 months-- but it seems apple doesn't bother to respond to a problem a lot of users are enduring.

did the extended hardware test-- hardware is fine.
did the clean-reinstall-- but problem still exists.
have reset pram-- and everything else suggested here.
even created new user account in case that might have been corrupted.

been a mac user for 10 years-- but come on apple-- *stop trying to be cool*-- and *get back to building computers that are reliable!!!*

if apple supports this forum-- then why can't they respond to a problem a lot of us are having?

incidentally-- this is the third time i've typed this-- since my imac keeps freezing!

Apr 12, 2008 9:06 PM in response to tahiti

I am also having the same problem as you, the horizontal lines and blured wedges. That has been happening for about a month now and it had froze a few times during that period. Now tonight it's froze about ten times and I can no longer start the system up and actually do anything before it freezes again. So I am completely stuck and writing this message from a much slower PC, but at least it's working for me. 😟

So hopefully you guys can get a fix before this happens to you. Should have put that new Time Machine to work, o well.

If anyone gets a clear answer from apple let me know because I am stuck here.

Apr 12, 2008 10:03 PM in response to tahiti

i have been having this problem for 2 months-- but it seems apple doesn't bother to respond to a problem a lot of users are enduring.

did the extended hardware test-- hardware is fine.
did the clean-reinstall-- but problem still exists.
have reset pram-- and everything else suggested here.
even created new user account in case that might have been corrupted.

been a mac user for 10 years-- but come on apple-- *stop trying to be cool*-- and *get back to building computers that are reliable!!!*

if apple supports this forum-- then why can't they respond to a problem a lot of us are having?

incidentally-- this is the third time i've typed this-- since my imac keeps freezing!

Apr 12, 2008 10:31 PM in response to tahiti

My computer seems to have better stability if I shut down and reboot as soon as I notice the weird screen artifacts. Also if I have to force quit, I reboot twice after that so I have done a normal shut down. I've disabled all the launch-on-mount applications to accommodate this. Turning on journaling (using Disk Utility) makes rebooting more reliable and much quicker after a freeze. It's like going back to the tricks you had to do to make System 9 stable enough to get work done. God help you if you add an extension, keep your SCSI cables short, and don't slam the door if you're burning a CD.

Apr 15, 2008 12:58 PM in response to dynamostia

I've had this problem as well; graphical glitches since upgrading to 10.5 with an eventual lockup. I have noticed it loves to lockup when I switch between different Spaces. The GUI is frozen, but I can still access the machine via SSH, and any sound that was playing (or video streaming to AppleTV) will continue with no problem.

Would really like to see this one resolved... the sooner the better.

Apr 18, 2008 10:53 PM in response to dynamostia

Following some suggestions on other forums about this identical problem with the 24" Aluminum iMacs, I started checking system temperatures with iStat Pro.

I displayed the GPU diode temperature in the menu bar and noticed it reached 65°C when I was doing some editing with Photoshop along with other stuff; a line of flawed pixels appeared, and soon the machine froze.

This only happened once, because then I installed smcFanControl and revved up the fans (1500-2000-1500 RPM) and now the GPU diode temperature remains below 50°C no matter what. And the machine is still pretty quiet, though not silent.

I have had the iMac running for two days now, trying to overload it (but no games or video). So far no bum pixels or freezing. Knock on silicon.

iMac Freezing

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.