2009 Early iMac Freezing 3.06GHz,24", ATI 4850

Hi all.

First mac for me so I'm probably missing out on obvious steps.

Similar to the issues other people are having, my computer is freezing up. What no other thread seems to mention is whether their macs freeze exclusively in OSX or in Windows as well (under bootcamp).

In my case its freezing under both and it doesn't happen in any particular moment. It can happen whilst playing a game or simply leaving the computer on at night.

I've tried the following tests:

· Apple hardware test - All ok
· Rember (GUI for Memtest) - All ok
· Repair disk permissions - There were many errors but fixing them didn't do anything

I have yet to try the "SMC reset" if I knew how to... anyone?

Remaining things to try:

· SMC reset
· PRam reset
· Reinstall OS (which option do i choose? Erase or not erase?)

· Phone Apple - I imagine they will keep me in hold forever and ask me to do a zillion tests so I want to try out all the tests I can so that the call doesn't become one of many.

iMac 24" 3.06Ghz ATI 4850 HD (Early 2009), Mac OS X (10.5.6)

Posted on Apr 16, 2009 6:55 AM

224 replies

Apr 21, 2009 5:55 AM in response to Community User

Having the same problems as others here: have a top spec 24" iMac which arrived on Saturday. Four freezes so far. All latest software fixes installed.

Apr 21, 2009 6:25 AM in response to Michael Haffey

Not sure I mentioned earlier but I'm certain this has nothing to do with third party software or other user-generated issues:

My first freeze occurred before performing any migration or installs -- before much of anything as a matter of fact.

I was sending an email out of Apple Mail to a friend - "Hey, I got my new Mac!" - and it locked. After that, it locked three times in succession while installing Logic (a long laborious install).

Inexplicably, but happily so far, the computer has not frozen since Friday evening. Knock on wood grain.

Apr 21, 2009 8:51 AM in response to Community User

Just got my imac 2 hours ago and it's one of the bad ones!

3.06GHZ INTEL CORE 2 DUO
4GB 1066MHZ DDR3 SDRAM-2X2GB
ATI RADEON HD 4850 512MB
APPLE WIRELESS MIGHTY MOUSE-Z
APPLE REMOTE
KYBD (NUM) & USER'S GUIDE-B
COUNTRY KIT,IMAC 24-GBR

I've got both WIFI and Bluetooth ON as I have a wireless mouse and cannot connect via cable to my router. Wired keyboard. Wireless mouse.

Freeze occurred within 10 minutes of startup while watching a standard def movie trailer in Quicktime. Second freeze occurred after restart while watching high-def trailer on Apple's trailers page.

Will do some more testing but for those of you who have got a replacement, what is the procedure? Do you just call the Applecare number?

Apr 21, 2009 11:10 AM in response to Hans Pans

http://www.bresink.de/osx/0TemperatureMonitor/download.html

Download this program and see how hot the insides of your imac are. If the GPU is reaching 60c then I'm guessing its an overheating issue (like mine). Open the fan control app and adjust the sliders to increase the fans RPM. If this works and your temps drop. You should be able to stream HD video all day.

Apr 21, 2009 1:49 PM in response to Community User

Got my new iMac 3.06 with the ATI card today. I got several freezes during installation, but after I installed the lates SW Updates it seemed to run smoothly. But nope, played WoW and after a while it froze.

Apple?

Apr 21, 2009 1:57 PM in response to Sweden1971

Has anyone who has gotten a replacement seen the problem vanish?

I haven't remembered the Mac freeze on me during regular use-- only during initial bootup (it spontaneously reboots, or freezes).

Apr 21, 2009 2:08 PM in response to =GreenTea=

I can say for sure it is not 3rd party related. Support got me to do an erase and install. The only disc I installed was the leopard disc, I didn't even install the application disc that come with the mac. Still got a freeze when viewing youtube.

Apr 21, 2009 2:35 PM in response to Community User

IMAC 24"/3.06/1TB/512/SD

So far:

4 freezes.

Suggested Fixes:

PRAM & SMC Reset : Fail
Erase and Reinstall System: Fail
Download and Install Fan Control Software: Fail

Not using WIFI and/or Bluetooth is not an option for me.

I can make the mac freeze by doing the following:

Open iTunes
Select any Internet Radio Station.
Press Play
Switch on iTunes Visualiser
Switch to fullscreen
Wait 20 minutes

System Freeze.

Have done this 4 times. Freezes every time.

Will have to send it back.

Apr 21, 2009 3:05 PM in response to Community User

This all sounds very disappointing. My iMac will arrive in a weeks time. Do people think this is something that can be fixed with a software update and i might as well leave my iMac boxed up until the issues are sorted. Or should i try and set up to see if does have problems. Are there any people with the ATI 4850 who are not experiencing freezing issues at all?

Apr 21, 2009 3:51 PM in response to Mr. Maintenance

So I can say, I had NO freezes since I only used the ethernet! Maybe that fixes the problem, but I'm not sure...

Apr 21, 2009 4:03 PM in response to Setanta2009

Update to my earlier post...

Been on to Apple who were very pleasant and pretty much immediately agreed to send me out a new iMac 🙂 (OK, I'd already done all the possible tests etc.)

Been doing a little research and while:

(a) I'm not a hardware expert
(b) These figures are mostly very general

I thought it was interesting...

Googling around for safe temperatures for various components I got the following figures:

CPU Max 100˚C Safe 80˚C
HDD Max 60˚C Safe 55˚C
ODD Max 50˚C Safe 45˚C
GPU Max 105˚C Safe 90˚C
Northbridge Max 105˚C Safe 80˚C
PSU Max 70˚C Safe 65˚C

In my case it wasn't the GPU which was overheating according to these figures but the PSU and Northbridge. I wonder if this is also the case for others ?

Setanta

Apr 21, 2009 4:14 PM in response to Setanta2009

Interesting news item regarding then new iMacs in October 7, 2007.

*Headline: New iMacs plagued by interface freezing issues*

http://www.appleinsider.com/articles/07/10/03/newimacs_plagued_by_interface_freezingissues.html

And then one from Sunday:

*New iMac owners see Radeon HD 4850-related lock-up issue*

http://www.appleinsider.com/articles/09/04/18/newimac_owners_see_radeon_hd_4850_related_lock_upissue.html

Message was edited by: famulous

Apr 21, 2009 4:47 PM in response to John Taylor9

Called Apple after running all the suggested Troubleshooting strokes in this thread. Reset PRAM on the phone with tech support and it froze. Product Specialist sounded well aware of the issue. I am receiving a replacement within the week. Not sure if replacing a broken wheel with one that may also be broken is quite ideal, but Apple's response has been stellar.

Apr 21, 2009 5:02 PM in response to cringeruk

The fact that users are seeing it in Windows as well doesn't bode well for a software fix, unless the software fix is reducing the clock speed of the chip.

It would be surprising for Apple to miss something that seems so easy to reproduce. One explanation for it would poor seating/connection of a key cooling element during a specific production run of units.

LanceFu

Level 1

0 points

Apr 21, 2009 5:09 PM in response to Aquapaddler

My iMac, which is also my first mac ever, has frozen 10 times already since I got it last Thursday. In 5 days, It managed to crash more often than the total amount of crash I has with my PC in 2008. I am getting tired of doing testing for Apple. What happened to Apple's QA?

Should I just ask for a replacement? If it's indeed a firmware issue, unless there's a newer version, I doubt it's going to help.

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2009 Early iMac Freezing 3.06GHz,24", ATI 4850