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SaSaSushi

macrumors 601
Aug 8, 2007
4,156
553
Takamatsu, Japan
I have hands like leather and they are not at all sensitive to heat and the case gets too hot for even me to touch for any length of time.

Please check the actual temperatures, people can't help you unless you provide them.

Exactly right and I would also tend to agree you have a defective machine if the case is getting that hot. Mine is warm to the touch at best right now and never gets uncomfortably warm to the touch.

Then again, I monitor system temps using the sensors Apple installed and not by touch anyway.
 

LJphoto

macrumors newbie
Jun 14, 2008
19
0
Please check the actual temperatures, people can't help you unless you provide them.

I told the tech at AppleCare what the temps were and he said they were normal, I told him the RPM's of the 3 fans, also normal. While I do not remember the temps off the top of my head I can tell you that they were comparable to what my 3 year old G5 Power PC was running at the same time and the tech said it was running at about the same temps as the one he was on when I called but his case was not too hot to touch.

I have a case with AppleCare and they are going to "get back to me" with an answer.

OK I decided to run the iMac for about 15 minutes and here are the readings from the istat and from my thermometers attached to the case:

Case temp (outside) 120-125 degrees

HD 124
cpu a 124
cpu a 133
gpu 148
gpu diode 142
gpu heatsink 139
ambient 92

Fan Rpm's

cpu 1198-1200
hd 1197-1200
optical drive 999 ETA optical drive jumped to 1500+ rpms not sure why...no disk is running and isn't that the cd/dvd drive?

Now they are a bit lower than earlier but I only had it on for about 15 minutes. The case is still pretty hot to the touch. The only program running at the time is iTunes.
 

sk8mash

macrumors 6502a
Dec 1, 2007
953
110
England
Firstly, contact is required for conduction. (Got dictionary?)

Secondly, air is a crappy heat-transfer medium for convection.
(That's why it's used as an insulator in double-glazed windows.)



...uh, lemme guess ...you're not an engineer or a physics major?

LK

It didn't say there didn't have to be contact for conduction to occur, but obviously there is contact as the innards are fixed to the case. I have a heater next to me, with no fan. WHen I turn that on the element lights up and the heat is spread quickly around the room via convection currents. In the iMac a fan assists that so that the heat is dispersed quicker (more efficiently).

Secondly I am not denying that air isn't the best material for transferring heat. Obviously a solid would act as a better conductor, HOWEVER air is still a good conductor of heat as proved by the heater next to me.

The iMac is designed to be AIR COOLED by direct-contact heat transfer
(conduction!) from the internal components to the fan-driven moving
air stream -- then out the rear vent. If the case is more than a few
degrees above room temperature, the cooling system is busted.

LK

Of course the iMac is air cooled, but this doesn't change the conduction properties of the aluminum (which has a high conductivity rating of 235). Do you not see the connection the Apple engineers made?

Judging by your knowledge, I guess you're not an engineer or a physics major?
 

LJphoto

macrumors newbie
Jun 14, 2008
19
0
It didn't say there didn't have to be contact for conduction to occur, but obviously there is contact as the innards are fixed to the case. I have a heater next to me, with no fan. WHen I turn that on the element lights up and the heat is spread quickly around the room via convection currents. In the iMac a fan assists that so that the heat is dispersed quicker (more efficiently).

Secondly I am not denying that air isn't the best material for transferring heat. Obviously a solid would act as a better conductor, HOWEVER air is still a good conductor of heat as proved by the heater next to me.



Of course the iMac is air cooled, but this doesn't change the conduction properties of the aluminum (which has a high conductivity rating of 235). Do you not see the connection the Apple engineers made?

But none of this changes the fact that if the case reaches a temp that is hot enough to be dangerous like mine did at 150 degrees F, that is not normal or good. Even the good people at AppleCare have conceded to me that there must be something wrong with my machine and recommended that I do not use it, or at least do not leave it unattended when it's on until the issue is resolved, whatever that resolution is.

If a computer is designed to get so hot that it could be a danger then the designers are stupid and I seriously doubt that is the case. The aluminum cases on the iMacs in the store when we bought the iMac just yesterday were nowhere near as hot as mine after just running it enough to set it up and for my son to start playing one game for about 10 minutes before it froze, and for it to have locked up at least 3 times when trying to do a shutdown or restart there is something wrong. I don't know what is wrong since the component temps and fans were within normal working ranges as evidenced by the iStat data and the Utility that AppleCare had me run.

I will post the resolution of the case when I have it. Unfortunately the tech assigned to my case is not available until Monday after 11:30 AM according to his voice-mail. After he had me run the system tests from the start disk which took more than 30 minutes, I was instructed to call back with the results which were all normal. When I called it went to voice-mail so I left a message. I called again a couple of hours later and left another message and then called back this morning only to get his voice-mail again only this time the voice-mail is telling me that he won't be available until tomorrow after 11:30.
 

sk8mash

macrumors 6502a
Dec 1, 2007
953
110
England
But none of this changes the fact that if the case reaches a temp that is hot enough to be dangerous like mine did at 150 degrees F, that is not normal or good. Even the good people at AppleCare have conceded to me that there must be something wrong with my machine and recommended that I do not use it, or at least do not leave it unattended when it's on until the issue is resolved, whatever that resolution is.

If a computer is designed to get so hot that it could be a danger then the designers are stupid and I seriously doubt that is the case. The aluminum cases on the iMacs in the store when we bought the iMac just yesterday were nowhere near as hot as mine after just running it enough to set it up and for my son to start playing one game for about 10 minutes before it froze, and for it to have locked up at least 3 times when trying to do a shutdown or restart there is something wrong. I don't know what is wrong since the component temps and fans were within normal working ranges as evidenced by the iStat data and the Utility that AppleCare had me run.

I will post the resolution of the case when I have it. Unfortunately the tech assigned to my case is not available until Monday after 11:30 AM according to his voice-mail. After he had me run the system tests from the start disk which took more than 30 minutes, I was instructed to call back with the results which were all normal. When I called it went to voice-mail so I left a message. I called again a couple of hours later and left another message and then called back this morning only to get his voice-mail again only this time the voice-mail is telling me that he won't be available until tomorrow after 11:30.

Yep, sorry, not meaning to hijack your thread. Just having a conversation about the general physics with that other guy.
 

LJphoto

macrumors newbie
Jun 14, 2008
19
0
Yep, sorry, not meaning to hijack your thread. Just having a conversation about the general physics with that other guy.

Actually this isn't my thread but I have the same issue as the op in terms of the hot case and I was hoping to get some insight or at least commiseration :p from others who experienced this issue while waiting for the AppleCare people to figure it out.

I jumped into that convo as well so I am guilty of hijacking the thread to some degree too.

In fact the op has not been back since they said they were going to run the machine and report the temps here.
 

sk8mash

macrumors 6502a
Dec 1, 2007
953
110
England
Actually this isn't my thread but I have the same issue as the op in terms of the hot case and I was hoping to get some insight or at least commiseration :p from others who experienced this issue while waiting for the AppleCare people to figure it out.

I jumped into that convo as well so I am guilty of hijacking the thread to some degree too.

In fact the op has not been back since they said they were going to run the machine and report the temps here.

Oh yeah, didn't notice that...my bad :D
 

jackmileshunt

macrumors member
Original poster
Jun 14, 2008
36
0
England
Stats

hello, sorry about this, (didnt realise id get this kind of response, and its probably me being parnoid lol).

the ones that really stuck out was (all in celsius)
CPU A 45
GPU 52
AMBIENT 32
AIRPORT 61

thanks:apple::apple:
 

jackmileshunt

macrumors member
Original poster
Jun 14, 2008
36
0
England
hello, sorry about this, (didnt realise id get this kind of response, and its probably me being parnoid lol).

the ones that really stuck out was (all in celsius)
CPU A 45
GPU 52
AMBIENT 32
AIRPORT 61

thanks:apple::apple:

sorry, yes was judging by touch at first, didnt think to check temps before being advised to
 

AlexisV

macrumors 68000
Mar 12, 2007
1,714
264
Manchester, UK
A lot of stuff to get through here.

Originally Posted by AlexisV

Computers get hot. It's what they do. ...

You don't turn off your car because you think the engine is too warm!

----So, why does virtually every car in the world still have a temperature gauge?

----...and why did Apple install so many temperature sensors?

You don't turn off your engine because you THINK it's too warm. The temperature gauge in a car tells you when it's too warm, usually when the needle goes into the red.
Apple installed so many temperature sensors so that you can surprise, surprise, check the temperature. Useful if your machine's fan is on constantly or you are suffering freezes and lockups. Not useful for the paranoid, but there you go.


A) The iMac is supposed to be air-cooled -- that's why it has three
fans inside. There is NO intimate contact between the CPU, GPU,
HDD, etc. and the aluminum bezel. As these photos clearly show,
the elaborate CPU/GPU heatpipe assembly is directly in the airflow
path of the large fan in the lower left-hand corner -- and has NO
significant path for thermal conduction to the case. Same deal with
the HDD: directly fan-cooled, with NO thermal bonding to the case.

Which would imply the top left of the case would never be warmer than room temperature. Guess what - my case is so hot I can't hold my hand on for more than 10 seconds.

B) If the case is hot, the stuff inside must be even hotter...

Yes, but the stuff inside would be HOTTER STILL without the case metal. CPUs don't have heatsinks for decoration.

Firstly, contact is required for conduction. (Got dictionary?)
Again, I'm 100% sure I'm not imagining the pain in my hand when I place it on the aluminium casing.

What I really want to know is how on earth it can be considered normal and acceptable for the aluminum exterior case of my iMac to reach a temp of 150 degrees F, enough to burn a toddler's hand even when the components inside are at "normal" operating temps?

For the same reason that your car engine would burn your hand if you put your hand on it. The heat produced by the computer components has to be dissipated somehow.

Oh and could the heat be the cause of the computer locking up at least 3 times when shutting it down? It just sat there with the gear spinner spinning for over 10 minutes when I finally just hit the power button...never had this with my G5.

No - overheating tends to make the whole machine freeze, whereas your icon was spinning. I suspect a process has interrupted your shutting down process.

I have a G5 Power PC which has never in the 3 years I've had it locked up. The iMac is new to me today and I am already very frustrated with it. First a game froze and the disk wouldn't eject. When I finally got it to eject it burned my hand so bad that I dropped it. I ran a diagnostic utility as per AppleCare and everything came back "normal". Istat says the fans are running and that the internal temps are fine but the case is too hot to touch and I would be afraid that a child would be hurt. I'm also a bit afraid of it catching fire. My husband actually had a monitor catch fire while he was using it. Smoke suddenly started billowing out of it and when we looked at the back of the case it was melted. So we are a bit scared to walk away from the iMac for that reason with it being so darn hot.

I got this one for my middle son who is college bound and now I have fears of him using it in a dorm. I'm afraid he will have papers too close and it will catch fire if it overheats.

I understand your concerns, but there is no reason to be so worried. The case does get very very hot, but if you were to take the side of a PC case and stick your hand in there it would be equally hot. The iMac is a laptop on its side with a screen next to it. It won't burst into flames. Guaranteed.

Remember they renamed laptops 'notebooks' because nowadays they burn your lap!

The iMac is designed to be AIR COOLED by direct-contact heat transfer
(conduction!) from the internal components to the fan-driven moving
air stream -- then out the rear vent. If the case is more than a few
degrees above room temperature, the cooling system is busted.

Utterly false. Cooling system busted my arse.

Do you even OWN an aluminium iMac???
 

eXan

macrumors 601
Jan 10, 2005
4,731
63
Russia
Apple installed so many temperature sensors so that you can surprise, surprise, check the temperature.

Actually, no. Apple installed so many sensors so that OS can monitor the temperatures and adjust fans' speed accordingly.
 

LJphoto

macrumors newbie
Jun 14, 2008
19
0
A lot of stuff to get through here.



You don't turn off your engine because you THINK it's too warm. The temperature gauge in a car tells you when it's too warm, usually when the needle goes into the red.
Apple installed so many temperature sensors so that you can surprise, surprise, check the temperature. Useful if your machine's fan is on constantly or you are suffering freezes and lockups. Not useful for the paranoid, but there you go.

Or when steam comes out from under the hood if the thermostat is busted...:p

I do have the istat monitors installed on both of my macs...one of the first things I did when setting the iMac up.

For the same reason that your car engine would burn your hand if you put your hand on it. The heat produced by the computer components has to be dissipated somehow.

Yes but I sure as heck wouldn't let a young child play around with the engine of my car, but I might let them use the computer.

No - overheating tends to make the whole machine freeze, whereas your icon was spinning. I suspect a process has interrupted your shutting down process.

The whole machine DID freeze up...I had to use the power button to power it down as per AppleCare's instructions when I called. AppleCare is conceding that there is indeed a problem with my machine.

I understand your concerns, but there is no reason to be so worried. The case does get very very hot, but if you were to take the side of a PC case and stick your hand in there it would be equally hot. The iMac is a laptop on its side with a screen next to it. It won't burst into flames. Guaranteed.

It is a worry because I still have a mark on my arm where it burned me. A shiny strip where my inner arm was touching it when I reached over it to get papers that were on the shelf above and behind it. It looks like it's going to flake and peel. And we did have a monitor almost burst into flames on us once so it CAN happen. The only reason it didn't was because my husband was using it when it started billowing acrid smoke. The whole back of the thing was charred and melted. It was defective and the company replaced it even though it was out of warranty by several months.

I did manage to do a temporary fix by putting one of my house fans next to the machine aimed right at the back and side of it. The case is not getting as hot, I can actually hold my hand on it without burning it and it only froze once yesterday requiring the power button to shut it down.

AppleCare is supposed to get back to me some time after 11:30 today with further instructions.

I will say that there is nowhere on the case of my PowerPC G5 that gets even remotely hot, slightly warm and I mean maybe just above room temp. AND the G5 has not ever in 3 years I've had it froze up on me not even once. I am a photographer using several editing programs simultaneously on the machine often doing batch editing. The inside temps do get higher than the iMac according to the gauges but it is a gem of a machine...I'm thinking I should have just spent the extra $$ on another one but my son doesn't need anything like that for school which is why I got him the iMac.
 

nickf

macrumors regular
Oct 2, 2007
110
141
Here's an interesting read for those concerned about the temperature of the HD bay inside their iMac.

http://storagemojo.com/2007/02/19/googles-disk-failure-experience/

Money quote: "Sudden heat death?

One of the most intriguing findings is the relationship between drive temperature and drive mortality. The Google team took temperature readings from SMART records every few minutes for the nine-month period. As the figure here shows, failure rates do not increase when the average temperature increases. At very high temperatures there is a negative effect, but even that is slight."

Interesting to note that over-cooling your HD can shorten the life just as effectively as cooking it.

Bottom line: Don't lose sleep over it. Unless you run your Al-iMac with a towel over the top or backed up next to a radiator you don't have much to worry about. And I'd be wary of installing any mods that play around with your default fan speeds.
 

AlexisV

macrumors 68000
Mar 12, 2007
1,714
264
Manchester, UK
Freezes are usually down to faulty memory sticks. Try reseating the RAM.

The cases on the white iMacs became warm rather than hot because of the different material.

Monitors are different from computers, vaccum cleaners, microwaves etc. etc. If my vacuum burst into flames it doesn't mean my microwave will too.
Sorry to be facetious, but whatever problem your machine maybe has, it ain't going to burst into flames.
 

LJphoto

macrumors newbie
Jun 14, 2008
19
0
Freezes are usually down to faulty memory sticks. Try reseating the RAM.

The cases on the white iMacs became warm rather than hot because of the different material.

Monitors are different from computers, vaccum cleaners, microwaves etc. etc. If my vacuum burst into flames it doesn't mean my microwave will too.
Sorry to be facetious, but whatever problem your machine maybe has, it ain't going to burst into flames.

Since the computer is brand new and under warranty and AppleCare I will let them do any work on it.

Are you going to guarantee me that a computer that gets hot enough to burn skin isn't going to catch fire? AppleCare told me NOT to use it until they get back to me with a solution which will likely be to exchange it. They have conceded that while it does get hot it shouldn't cause injury which it already did.

Of course I know that monitors and vacuums are not the same, but when you have an electronic device that actually gets hot enough and burns the skin on your arm to the point where it starts to flake and peel I won't bet my life on it NOT possibly catching fire when I walk out of the room...maybe there is a problem with the power supply, a short somewhere or something that is causing it to get so hot on the case, I don't know but I am not willing to risk my life and home on it. I almost learned the hard way once.
 

Leon Kowalski

macrumors 6502a
As the figure here shows, failure rates do not increase when the average temperature
increases. At very high temperatures there is a negative effect, but even that is slight.

Might be a good idea to check their definition of "very high temps."

The extreme upper limit of "very high temps" in the Google Labs'
study is BELOW the temperatures routinely reported (here, and
on discussions.apple.com) for idling internal drives in ALU iMacs.

Bottom line: Don't lose sleep over it.
Bottom line: You snooze, you lose!


...no wurries, it ain't my hard drive,

LK
 

LJphoto

macrumors newbie
Jun 14, 2008
19
0
Update

AppleCare called me back about the issue a little while ago. They told me that the aluminum case does get warm, very warm but it should not get as hot as mine did...it should not burn like mine did or reach a temp of 150 degrees on the outside even with internal temps higher than that. They are concerned about it because it is dangerous for it to get that hot on the outside. They told me that I will need to take it back to the store where I got it (an Apple Store) for the exchange. They are contacting the store to set up the exchange for me. I am supposed to get a call from the store manager shortly. I should be able to return it later today. All's well that ends well...I hope!
 

LJphoto

macrumors newbie
Jun 14, 2008
19
0
Update

I returned the iMac to the store to have it tested and the tech told me to just exchange it. (It was within 14 days of purchase so I could return it as "not satisfied".) He also told me that he had definitely had some of the display models get too hot and there are sometimes problems.

At any rate they took my "old" machine and migrated all my stuff onto the new one and I picked it up the next day; yesterday. My 18 year old son played games on it all afternoon and I am happy to report that it is running at much lower internal temps according to the istat, the case is nowhere near as hot as the other one and it did not freeze up once. All's well that ends well!
 

Leon Kowalski

macrumors 6502a
I am happy to report that it is running at much lower internal temps
according to the istat, the case is nowhere near as hot as the other
one and it did not freeze up once. All's well that ends well!

Oooh! Better take it back to the Apple Store and tell 'em something
must be seriously wrong with your new iMac...

...'cause it's not running as hot as AlexisV's "known good" machine,

LK
 

Halon X

macrumors regular
Sep 22, 2005
208
0
Malibu, CA
I've never understood why people worry about the case of their iMac feeling too hot to the touch? What are people doing touching it that they need to worry, it's not like it's a laptop sitting on your lap!

I trust the Apple engineers to know enough (a heck of a lot more than me at least) to design the computer with a proper case, adequate cooling and enough fail-safes to protect the system should it ever overheat.
 
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