Freezing iMac Issue Due to Hardware?

[Mindflux]

I'm a recent switcher and this is driving me insane. I NEVER had this many problems with a Windows machine in the past 10 years. After 2 calls to Applecare, Apple won't acknowledge the problem because I can't recreate it on the phone. I think having to send in my brand new machine for repair is unacceptable. I'd be more than willing to swap out my 24" machine at the local Apple store with a working unit.

You can't re-create it on the phone?

You: Yeah my iMac locks up (etcetc )
Apple: Lets see if we can re-create it
You: yeah I just move my cursor around over the dock and open iPhoto and hold my tongue out right.
Apple: ok, do that
You: OH MAN IT LOCKED UP (did it? Do they know? are they spying on you through your camera?)
Apple: please take to xyz.
You: (Thinking to self) damn it was that easy?

 

[Mindflux]

By jove, the lad might have something here, anybody else try using SMC?

Yep, lots of users running SMC with no luck. I, fortunately have not had a lockup yet.. so no need to crank my fans.

 

[pavelbure]

"I called this ages ago"



With all due respect, those folks that said this are not proven to be right at all. Again, AppleInsider is known for posting crap. And this article could likely be no different. Especially as it appears to be a user submitted story.

agreed, like what has been said before, my imac froze 100% of the time coming out of sleep mode. when it was cold.

my video card was just replaced today, i ran leopard on it for about 5 min. and didn't freeze using the usual programs. i will play with it more this weekend.

 

[flopticalcube]

I'm a recent switcher and this is driving me insane. I NEVER had this many problems with a Windows machine in the past 10 years. After 2 calls to Applecare, Apple won't acknowledge the problem because I can't recreate it on the phone. I think having to send in my brand new machine for repair is unacceptable. I'd be more than willing to swap out my 24" machine at the local Apple store with a working unit.

This is what I did. The next time it locks up under OSX, press the power button twice then wait. The machine will take a minute or two to go to sleep. Wait another minute then press the power button again and the machine will wake up and kernel panic. Reboot the machine according to the instructions on the screen. After the machine reboots a little box will pop up telling you that your machine rebooted because of a problem and do you want to report it to Apple. Choose report and fill in the details in the various panes as best you can. Then call Apple and they will be able to see the kernel panic report. That usually shuts them up.

 

[*GG*]

I have said to many people now - if you are thinking of buying an iMac - forget it. This is my first and it is the most unreliable computer I have ever bought. Applecare say they can't do anything. They won't take the machine back, and the whole experience is simply frustrating.

I did keep hoping that some kind of software update would solve the problem - but this news today has really brought me right down.

 

[Cheffy Dave]

ATI could not cool an ice cube; the pathetic cooling system on my x800 failed about a year ago. The stupid heat sink is actually held on the boards by solder.. yes SOLDER! Lets see, we need to cool something that gets insanely hot, so lets attach it by something that turns to liquid under heat. Brilliant plan.

-mark

I had ATI problems with the same card, but there is no PC that gets hot enough to liquify solder without bursting into flames

 

[TheRuggedLion]

If its a hardware issue, how come I can load into Windows XP and game for a few hours without a single freeze?

 

[Cheffy Dave]

Too True! As soon as the alum imac came out I went out and bought a sweet 24 inch White imac demo unit.


Best thing I ever did... although i have to sink some more ram into that puppy.

HMMMMMMMMMMMMMm, they have a nice one at Smalldog.com for $1495

 

[mrobison]

umm...

Just throwing this out there, but I bought a 24" 2.4 about the thursday after launch and got it about August 15. I almost always leave the computer on (sleeps all the time) and have only rebooted for software updates. I run the iStat widget to monitor stuff, and I have never seen the GPU higher than about 105 or so, but the Airport card always hovers at about 125, so I don't think it's heat. I've never had it freeze, nor had any problems except for a single dead pixel in the bottom left corner that I've noticed maybe half a dozen times. I've done a fair bit of video work in iMovie, a little Doom 3, and have had no problems at all...

Am I just lucky?

 

[l33r0y]

Just throwing this out there, but I bought a 24" 2.4 about the thursday after launch and got it about August 15. I almost always leave the computer on (sleeps all the time) and have only rebooted for software updates. I run the iStat widget to monitor stuff, and I have never seen the GPU higher than about 105 or so, but the Airport card always hovers at about 125, so I don't think it's heat. I've never had it freeze, nor had any problems except for a single dead pixel in the bottom left corner that I've noticed maybe half a dozen times. I've done a fair bit of video work in iMovie, a little Doom 3, and have had no problems at all...

Am I just lucky?

I guess so.... so far anyway.

Othe users are reporting they have had no issues from the start but are getting freezes recently.

Are you using Tiger or Leopard?

 

[Whoshnot]

Just throwing this out there, but I bought a 24" 2.4 about the thursday after launch and got it about August 15. I almost always leave the computer on (sleeps all the time) and have only rebooted for software updates. I run the iStat widget to monitor stuff, and I have never seen the GPU higher than about 105 or so, but the Airport card always hovers at about 125, so I don't think it's heat. I've never had it freeze, nor had any problems except for a single dead pixel in the bottom left corner that I've noticed maybe half a dozen times. I've done a fair bit of video work in iMovie, a little Doom 3, and have had no problems at all...

Am I just lucky?

No, you are not alone. I bought an iMac last month ... it has not frozen a single time with 10.4 and also not with 10.5 now, although I have been playing some games lately. All the sensor temperatures are rather low IMHO, certainly compared to my old iMac G5.

It could be that only a small percentage of iMacs is affected. But that would still be a huge number of macs if you consider how many of these Apple sells... which explains such a total number of freezes after all.

 

[ascender]

How can it be heat related when many people suffer the problems from a cold boot?

 

[gwangung]

Given all the info given out (happens after a cold boot! Never happens in Boot Camp! It helps to keep the fan on!It happens after I upgrade to Leopard! It did it before Leopard!), I suspect Apple is getting driven crazy trying to pin this down.

Not to excuse the problems, but I'm not wondering why Apple is keeping mum on this problem (particularly if it turns out to be 2 or 3 problems instead....)

 

[mrobison]

I guess so.... so far anyway.

Othe users are reporting they have had no issues from the start but are getting freezes recently.

Are you using Tiger or Leopard?

I'm currently using Tiger, but was about to update Leopard. I decided not to until some more of this is resolved and they come out with 10.5.1 at least.

Update too- I played Doom 3 for about half an hour and checked the temp again; its now at about 130ish, but still not ridiculously high...

 

[Marble]

I don't see how this can be a heat issue. I can be using my computer dandy as a dog for hours or just for seconds and then it'll freeze when I do something specific, like run my mouse over the dock. You think the GPU is accelerating from normal to extreme temperatures in the fraction of a second it takes to roll over the dock?

 

[FakeWozniak]

Other Factors?

Through the various crashes, I have noticed that sometimes the wireless keyboard and wireless mouse still "seem" to work. Sometimes the cursor moves on the screen with the mouse movements, but clicking doesn't work and neither does the button help. Also the caps lock LED will sometimes toggle. I know from prior programming experience that the cursor is drawn at vertical retrace interrupt, so I known both the VR, USB, HID, and bluetooth device drivers are running. My keyboard is the pre-aluminum Wireless keyboard.

I wonder if the network would allow SSH connections. Anyone try? Does ping work when it is locked up? I will try this and report back.

Anyways, before I learned others had the same problem as me, I just thought the problem with the mouse and keyboard were bluetooth related because of weak batteries, or other bluetooth devices in the house (PS3, other macs with BT keyboards and mighty mice). I do recall I got relief when unplugging them.

Is it common for other people getting the freezing to be using bluetooth?

I have my 802.11 shut off, so I don't think that is interfering. I will go back to wired keyboard/mouse and report back.

Oh, one more thought. I have been using Parallels 2.5 (latest build) and wonder if that installed any kernel stuff that might be hurting me. I saw on their website they are aware that Parallels Desktop 3.0 and 2.5 have Leopard problems and only 3.0 has a patch (I think).

Other than Parallels, I only really run iLife 08 and Office 2004.

My printer is a Canon MP830 directly connected.

 

[robby818]

Has this been an issue for anyone using their iMacs to run Windows in bootcamp?

I run XP on a 24" Al iMac, leave it on most of the time (not in standby because it doesn't work right) and have not had any freezing issues in the month that I've owned it. The iMac runs pretty cool most of the time (placing a hand on the back and top). Seems that the backlighting for the screen generates the most heat.

 

[flopticalcube]

I wonder if the network would allow SSH connections. Anyone try? Does ping work when it is locked up? I will try this and report back.

People have successfully ssh'd into their frozen iMacs and performed clean shutdowns. Furthermore, you can usually get it to go to sleep (using the power button) and it will then kernel panic when you wake it up.

Has this been an issue for anyone using their iMacs to run Windows in bootcamp?

I run XP on a 24" Al iMac, leave it on most of the time (not in standby because it doesn't work right) and have not had any freezing issues in the month that I've owned it. The iMac runs pretty cool most of the time (placing a hand on the back and top). Seems that the backlighting for the screen generates the most heat.

Yes. I have had it hang in XP. Not as often as OSX or as repeatable but it does happen, usually during gaming.

 

[Infrared]

The smart thing to do is run smcFanControl 2.0 until Apple issues a fan firmware update. I've built a lot of computers in my day and I know that stock for stock the iMac fans spin way too slow. Bump them up from 700/1200/1200rpm to 1500/2500/2000 it's still really quiet. The components don't get nearly as hot. I run 2600/3340/2300 during gaming and encoding. Heat could have been an issue, but I've been running SMC since the week I bought the new iMac, so it's possible I haven't fried my components like some people might have by running stock fan speeds.

And maybe this explains why I can go 6 hours on end gaming without an issue, 10 hours of video encoding without an issue and so on for the last 2 months.

Is that really the smart thing to do? Suppose it just prolongs
the period before your gfx card fails taking you out of the
warranty period? What about wear and tear on the fans?
Etc. etc.

Apple's engineers have chosen those fan speeds for a reason
and I think it's presumptuous to think you know better unless
you also happen to be an engineer that specializes in this area.
They're not completely stupid, you know. If it was that obvious
the fans run too slow, they would have dealt with it ages ago.

 

[flopticalcube]

Is that really the smart thing to do? Suppose it just prolongs
the period before your gfx card fails taking you out of the
warranty period? What about wear and tear on the fans?
Etc. etc.

Apple's engineers have chosen those fan speeds for a reason
and I think it's presumptuous to think you know better unless
you also happen to be an engineer that specializes in this area.
They're not completely stupid, you know. If it was that obvious
the fans run too slow, they would have dealt with it ages ago.

MTBF of fans is huge. They probably set the speeds as low as they can for noise reasons. Jobs would rather have no fans at all.

 

[Infrared]

Actually, it just makes me glad I saved some money and went with the nVidia card that it comes with.

Quieter too

All this kind of makes me wonder why Apple use so much ATI stuff
for OpenGL-based systems. The received wisdom (right or wrong)
is that ATI lean towards DirectX and it's Nvidia that write the better
OpenGL drivers.

 

[AlexisV]

I'm skeptical for a few reasons:

- an overheating problem would indicate the cooling is very marginal, which would surely mean everybody would be having problems of various intensity over a period of time. Instead we have the situation where thousands of machines are faultless and others freeze very frequently. It would also mean that those will faultless machines would be bumped into the 'overheating' category by merely exercising the GPU and CPU. Whereas in fact, flawless Macs maintain their flawless performance when pushed to the limit in games for example.

- the artifact issue is a sign of faulty GPU, not just an overheating one. A GPU can quite easily have artifacts and freeze the machine just because it was born a faulty piece of hardware. You'll always have these problems with a certain percentage of silicon. However, it's easy to report such problems to the world on Apple forums. Have the same problem with a brand new Packard Bell PC for example, and you'll really only have the option of posting at one of the hundreds of generic PC forums.

- Apple has released a statement and thinks it is software, not hardware related.

- If the guy on Applesider thinks they replaced the GPU (how does he know this), surely he just had a faulty GPU on his particular machine?

- We never hear whether the problems affect the 2600 and/or the 2400.

Now I'm not saying the problem doesn't exist and I don't want to sound unsympathetic if you have a dodgy machine, it's just that the design flaw idea doesn't stack up.

I suspect there's a combination of faulty Radeon chips out there AND there is some software issue that Apple is trying to fix. I have no idea what this software issue could be trying to fix since every machine should be identical, but the EFI will control things such as voltages to the GPU. Different batches of chips produced at different times in the same factory can react very differently to voltages, as CPU overclockers will know.

 

[CIrawI3riCIge]

hmmmm

Wonder if it has anything to do with this (although AMD denied such rumors ):

Headline: AMD software let defective graphics cards slip into the channel

http://digitimes.com/mobos/a20070801PD209.html

 

[t^3]

I work at a university computer lab, where we had some Dell Optiplex 740's which were having freezing issues and BSOD's at random. They have a Radeon HD 2400 XT, pretty much similar to the IMac's video chipset. A few weeks ago, Dell came out with both a driver and video BIOS or firmware update, and all is good now. For us, it was definitely not a heat issue, as we had a problematic machine that sits right under an air conditioning outlet, so it was one of the coolest machines in the room. It turns out that the updates disabled the Dynamic Power Management (DPM) feature of the video cards.

I have a feeling that this problem is hardware-specific, but actually due to firmware and not heat, and Apple should look into applying a similar update to the iMacs that disables DPM.

 

[Infrared]

Leopard is another interesting thing with these freezing iMacs.. There are quite a few folks that say it made the freezing problems worse for them. But for my iMac it improved things substantially. Its not perfect, granted, but for whatever reason, it is definitely a lot better.

All this reminds me of the time my linux laptop was freezing when
playing a game. I just couldn't figure it out. Some days I could play
for hours without any problems, and others it would lock up almost
immediately. It turned out the problem was dual-booting. If I'd
previously booted into Windows and not powered off before booting
into linux, I'd get the lock-ups. So there was some sort of stored
state from when I'd run Windows that was messing with the card
when I was running linux. I imagine the same thing could happen
with Windows on a Boot Camp partition and OS X, though I admit
it's hardly likely to be the cause of the problems discussed here.