Q: Burning Hot

Hi Brad87: Please download, install, and run iStat Pro and report the temperatures, and fan speeds back here.

http://www.islayer.com/apps/istatpro/

Stedman

I won't address the speed issue as you double posted that in another thread that I just replied to.

However regarding your temps, it's just fine and operating well within normal. All in One computers tend to run warm, if your computer was running in the 85 degree range then you may have something to worry about. However because it's not, simply forget about it and enjoy using it.

Also another thing you can do is empty some of the caches, this may help it out too. You can do this easily by starting in Safe mode. To start in Safe mode:

• Be sure the computer is shut down.
• Press the power button.
• Immediately after you hear the startup tone, hold the Shift key. The Shift key should be held as soon as possible after the startup tone but not before.
• Release the Shift key when you see the gray Apple icon and the progress indicator (looks like a spinning gear).

This cleans out the fonts cache (a major hog) and may speed up your startup.

Other thing you can do is download and run OnyX, this is a free utility. You can Google it to download and find out more information about it.

Regards,

Roger

Sorry you don't believe me however I think if you do a search on these and other forums you will find they are fine. Also feel free to contact Apple, you have 90 days of free telephone support (the number is in your manual) and/or you can bring it into an AASP to be looked at.

Apple has built in safeguards into their machines for heat, if the machine is nearing the limit it will put up a warning message and if that message is ignored the machine will shut down to protect itself. Those temps are well beyond what you have posted.

You are placing your hands right on the exhaust, it's kind of like a car if you put your hand on the exhaust you'd probably burn your hand there too.

Brad87:

In what context is literally used? If it's real hot that it actually burns ones hand then you should take it to Apple. But, if it is that hot then it should of shut down automatically. Compared to my temperatures, two of your items are about 10 degrees higher then mine-your HD temp. and the CPU Heatsink. If your GPU Diode is the same as Graphics Processor, then you are about 11 degrees high. These are my temperatures during normal use. I suggest you take it to Apple to have it checked.

It is normal because starting with the Late 2009 models Apple went to an all aluminum "unibody" case for the iMac. Before that they had a largely plastic shell with some aluminum siding/bezel. The new cases conduct heat OUT of the system much more efficiently, which is what you're feeling.

The entire case is functioning as a giant secondary heatsink/spreader.

And just a few lessons you appear to have forgotten from high school level chemistry/physics. Heat rises, heat travels from hot to cold, and not all materials are equal when it comes to conducting thermal energy.

Now, you could say that Apple has done a poor job of educating owners about this apparent change in behavior, and you'd have a fair point. But the simple fact of the matter here is that there is NOTHING WRONG.

Here's a little science experiment you can do if you don't believe me. Get a pot of water, and put it on the stove. Turn the stove on, and put your finger into the water. Leave it there until it's uncomfortable. How long does it take? Maybe 5-10 minutes? How long do you think it would take for the heating coil UNDER the pot of water to heat up enough to burn you? The heating coil is made up of a material that gives up heat much more readily than water. It will feel hotter to the touch, even if it's at exactly the same temperature as the water. The coil has less thermal resistance. That's why heatsinks usually use a material like copper for the core, as opposed to say iron. You want a material that will absorb and release heat readily, and iron is the opposite of that, just like plastic.

So, here's another simple science experiment, since we know heat runs from hot to cold, and when something feels cold it's because it's absorbing heat from your hand. We perceive that transfer of energy as cold. So go get a can of pop/soda out of the fridge. That aluminum can feels pretty cold, doesn't it? And it doesn't take very long to get uncomfortably cold, does it? That's the exact same principle you're complaining about, only in reverse.

And feel free to ask any high school science teacher about any of this. They'll tell you what I've said is factually correct. College physics professors, college chemistry professors, anyone who's taken a couple of college chemistry or physics classes... They will all tell you the same thing. And people question the value of all those general education classes you have to take to graduate! THIS is the value, right here. That knowledge, plus maybe 10-15 seconds worth of thought putting it all together, would have provided the answer to this before there was ever a need to post.

That's still not terribly useful as a measure. Some people like their showers to be nice and hot, others more lukewarm. Everyone's idea of hot and cold is different. I can't sleep if it's below 65F, but others consider that a pretty ideal temp. I'll still be wearing pants and long sleeved shirts when it's 75F out and be perfectly comfortable.

Anyway, I don't normally like to do this, I prefer to let my posts speak for themselves... But as an ACMT (meaning I have the same training and certification Apple store repair <Edited by Host> have), I'm telling you those temps are within range. They might be a bit on the upper end of things, but that could easily be explained by environmental factors. And if the system starts getting too hot, the fans will kick it up a notch or two.

So, I'm not just some random idiot on a message board who may or may not know what they're talking about. I don't work at an Apple store, but I do pretty much the same thing for a living right now. Systems come in, I figure out what, if anything, is wrong with them, fix them, ship them back out. You can take the system somewhere, but you're just going to be wasting your time, not to mention risk damaging your system by transporting it.

Brad87 wrote:
Anything else I'm supposed to do besides starting it up in safe mode?

No, after it has started in Safe Mode it's OK to run it for a few minutes. Here is a link to an Apple advice letter that describes what Safe Mode is:

http://support.apple.com/kb/HT1455

Never done it before and does that automatically delete that cache you were talking about?

Yes it does.

One last thing you can ensure your machine has adequate ventilation too, if you have pets or live in a dusty area you would be shocked to find out how obstructed vents can affect your temperatures. Cleaning them is fairly simple, shut down the machine, unplug everything, place it screen down on a table covered with a towel and vacuum the vents at the bottom of the machine. Here is a link to someone that just posted their experiences.

http://discussions.apple.com/thread.jspa?threadID=2560143&tstart=0

Roger

The sleep thing could be due to several factors, not the least of which is that you have more programs running which need to be suspended so it takes a little longer.

Heat typically doesn't cause a computer to slow down. That is USUALLY a software issue, though sometimes it can be a failing HDD. So if the only reason you're chasing this whole temperature thing is because you think it's making your system slower, then you're going to be running yourself in circles for a very long time.

Safe mode/boot, as suggested, is a good first step to try and isolate what exactly is the problem. If things work better in safe mode, then you get to have fun going through each and every one of your programs.

You can also toss Apple Hardware Test into the mix. There's a small chance of a bad HDD on your system, but it really sounds like your system just has a generic software issue.

<Edited by Host>

Brad,

With all due respect to rkaufmann and Scott,Billings you are right to be concerned about the temperature of your Mac. Heat is the enemy of electronic components and excess heat will shorten their life. The issue here is a matter of degree, and just what represents “excessive” heat. Personally, the temps you report (and that rkaufmann indicates are “just fine”) would concern me. You say your iMac has “always run very hot”. Is it your impression that your Mac is running hotter now, or essentially the same as it always has?

If you take enough time to search through this forum, you will find hundreds (thousands?) of cases of 3-4 year old iMacs with heat-related failures which manifest themselves as frequent screen freezes, graphical artifacts (lines, tearing, etc.) on screens, kernel panics, etc. The problems reported by others seem to be frequently associated with dying GPUs, which, as your temps also indicate, is generally the hottest internal location, as reported by the iStat Pro widget.

It’s always a good idea to be aware of overheating conditions and take steps to mitigate them if they’re excessive. I would say step one is to make sure you put your Mac in a favorable environment – that “seems” to be good in your case, 25 deg. C, but make sure you have good air circulation as well as a clean, dust-free environment.

As blasphemous as some will find this suggestion, I’m also in favor of downloading one of the 3rd party fan control programs (SMC Fan Control, or iMac Fan Control). In what seems to be a favoring of ambiance over heat/temperature control, Apple engineers have implemented fan control algorithms that keep fan speeds low (i.e., quiet) until temps get quite high. These 3rd party fan control programs allow you to increase these fan speeds above the Apple minimums and help drive temps down a bit.

Having said all this, perhaps your biggest culprit is whatever is causing your Mac to slow down. The cause of that is also likely to be causing your system to work harder and therefore run hotter. (Going back to my question in the first paragraph above, this would suggest your iMac is running hotter now than on day one) Finding the cause of this should be priority one. Definitely contact Apple. You’ve paid for Applecare, might as well use it.

Good luck, and keep the forum posted on whatever you may find.

I'm also a believer in keeping heat generation things cooler. For example, installing 3rd party Fan control program and manually adjusting the fans for one's common usage. IMO, applying more cooling before the temps get too hot is a good thing.

If wondering, the internal temps of my iMac 21.5" unit is:

http://i178.photobucket.com/albums/w251/Spike99-Pictures/New%20iMac%20system/Int ernalTempson2010-08-22at91948AM.png

Good luck...

.

Message was edited by: Jack99