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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

Best reply

rkaufmann87

Level 10

141,342 points

Posted on Apr 16, 2009 7:02 AM

Below are instructions on how to do SMC and PRAM reset together:

1. Turn off your iMac and unplug everything from it for 30 seconds.

2. Plug in the power cord, keyboard and mouse only.

3. Press the power button and immediately hold down the Option, Command, P & R keys until you hear the second gong then release the keys. Your machine will start up normally, then check for the issues you are having.

View in context

224 replies

Apr 20, 2009 8:25 AM in response to Hans Pans

Currently I have
CPU heatsink: 97º F
Internal HD: 121ºF
Internal DVD: 105º
GPU Heatsink: 111ºF

This is in a mostly idle state: I'm running Safari (obviously), iTunes on random play and the System Prefs. I will take a look at what these numbers look like during a recording session with Logic at a later date.

Sermon

Level 1

9 points

Apr 20, 2009 8:33 AM in response to Community User

Question for everyone with a 4850 iMac - are people who use Ethernet experiencing any freeze or lock-up problems? There's a theory over at the Macrumor.com forums where it's being discussed that this could be a WiFi issue ...

Apr 20, 2009 11:43 AM in response to Community User

I am another recent imac owner who is experiencing random crashes as described above. So dissappointing. I have owned and used macs for more than 10 years and never had recurring crashes. I think I will wait a week before calling apple so that they might have a better understanding of a fix. My hope is that by posting, I will help get apple's attention because this is NOT acceptable.

Jim Kohn

Level 1

50 points

Apr 20, 2009 12:30 PM in response to Tenesmia

Is there a consensus that installing Fan Control (http://www.derman.com/Download/Special/iMacFanControl.html) resolves the freezing issue? Is this somehow related to 3.06 processors showing up as 3.60? My iMac is on order, but not shipped yet. I'm thinking about canceling, but if this is truly a resolution, I'll leave the order active. Migrating to a new computer is time consuming enough, I don't have time for this additional headache right now.

Apr 20, 2009 12:36 PM in response to Sermon

I will try that... I hope that there will be a fix soon! =( I've been so lucky when my new iMac arrived today and then those freezes! 😟

Sermon

Level 1

9 points

Apr 20, 2009 12:54 PM in response to Mr. Maintenance

Could be just a coincidence, but as it is NONE of the iMac users who connect to the internet via Ethernet are experiencing ANY lockup/freeze problems and ONLY people who connect to the internet via WIFI do.

Apr 20, 2009 2:28 PM in response to davidbgreen

I've got the same. 5 days old, barely unboxed, and five freezes. I get maybe an hours use out of it. There's no way I can spend days jumping through hoops with system reinstalls and configuration issues. It arrived broken, it goes back broken.

Unless the 10.5.7 update fixes the issue. Here's hoping.

Apr 20, 2009 2:49 PM in response to Sermon

Well, I had no Freeze when I used Ethernet... I just disabled AirPort and plugged in my cable... Maybe that's the point. But what has this problem to do with the ATI graphics card? confused

Apr 20, 2009 2:53 PM in response to talamhaneisc

I'm having the same problem. I've bootcamped this machine with Windows Vista, which is locking up; I haven't yet had it lock on the Mac side. However, before Vista crashes, the BSOD flashes quickly on the screen with the error (I'm remember offhand here):

internal powererror

And dumps out the memory stats and the like before completely rebooting.

Doing some digging around on this error message, it seems to be related to improper bios voltages being set; basically, one component requires more power than its getting, so it fails during some task. In this case, I'm suspecting the component in question is the ATI video card... but I'm not sure if it is indeed the wireless card that's at fault. I've turned it off in Leopard, but I haven't tried to do that in Vista.

I'd love to hear what others have discovered, and if it's simply a BIOS tweak that Apple needs to develop.

Thanks !

Message was edited by: =GreenTea= (Clarified under which OS crashes occur)

ShuMac

Level 1

8 points

Apr 20, 2009 3:07 PM in response to Hans Pans

I installed iMac Fan Control.

My readings are:
CPU -- 100F -- fan 1800rpm
Internal HD -- 119F -- fan 2600rpm
Internal DVD -- 106F -- fan 1700rpm
GPU Heatsink -- 112F

I hope this gets resolved soon... 😟

Forgot to mention ... We are only using airport / no ethernet.

shinkfam

Level 1

0 points

Apr 20, 2009 3:13 PM in response to Community User

I too have the same problem with my 24" Ati 4850 iMac freezing up.I've called tech. support many times and they all say: "this is the first time they have heard about this problem", you would think the tech. support guys talk to one another? I guess not.
They all offer to send me a new computer, how can the problem be the computer when so many people are having the same issue? After reading a post on this site about downloading temp. monitoring,fan control software I tried it and it worked, I raised the low fan speed settings up and watched the northbridge temp drop 10c, I have watched 4 HD trailers and no lock-up. maybe this fixed it!!!!

I will keep everybody informed of any changes, hopefully apple will come out with their own fix for this problem.

Apr 20, 2009 4:57 PM in response to Community User

I think everyone here should try installing the "fan control" application to see if it fixes the problem. I have set all fan speeds to 2200 RPM with a low threshold of 30c and high threshold of 70c. So far everything has been working perfectly with these new settings...seems like this issue is fixed.

Apr 20, 2009 10:08 PM in response to Jim Kohn

Add my computer to the list. Same specs- 3.06 Ghz, 24", ATI 4850. Just pulled mine out of the box on Saturday. I have had over a dozen crashes since then. Simple browsing, playing iTunes, or installing Logic. Calling Apple in the morning.

oracle

Level 2

175 points

Apr 20, 2009 11:12 PM in response to Community User

Hey there,

I was wondering if anyone has any pblm with OS X Server installed on this iMac ?
Same issues ? freezing ?

Thanks

Apr 20, 2009 11:45 PM in response to revolvingiris

I installed the imac-fan-control app. it seemed to go ok, until my girlfriend started watching shows on mtv.com. (those are flashmovies I believe). She was watching it fullscreen and the imac locked up a couple of times.

That's more than during the day while I was working for 8 hours, only locked once during the day.
My working day consisted of typing a document in pages and using safari & mail
(yeah it was a boring day...)

working on wifi, btw.

HP

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