Upgraded iMac heat questions

I'm considering purchasing a top-tier 2011 iMac. I'm on the fence whether or not I should have them customize it to have a 3.4ghz i7 and 2GB 6970M... or just go with the standard 3.1ghz i5 and 1GB 6970M. Will the upgraded model run significantly hotter? I'm just worried about heat because I know that it can potentially kill the machine if you're not careful.

Thanks in advanced...

An iMac runs cool compared to a MacBook or MacBook Pro. It has three fans one of which is dedicated to the hard drive, one for the CPU, and the third for the optical drive. It's vented at the bottom of the display to draw in cool air and vented at the top to exhaust the warm air.

What do you intend to use it for that requires the faster CPU and GFX card?

I have yet to see mine even get warm...

I worry about the temps on my iMac sometimes, i have the top model of the 2010 27" iMac, and i have to say when im using programs like handbrake to convert videos etc, do a bit of browsing and use itunes it gets hot.. using handbrake seems to cause it to get very hot, the temps dont actually look that high however the back of the machine is so hot i cannot keep my hand on it for more than a few seconds, at this point the CPU fan is running at around 1800 - 1900rpm... not sure if its normal for the aluminium on the back to get so hot, but its never overheated or shut itself down so im not to worried, anyone else noticed this with thier imac?

What you're experiencing is normal. As I stated above, an iMac has three fans. The two you should be concerned with when converting videos is the CPU and hard drive fans. Normal speed for both is around 1200 RPM with a temp of around 35〫to 40〫C. The aluminum back plate acts like a large heat sink and gets warm during any kind of heavy activity.

Put your hand over the top vent when you're converting videos for any length of time and you should feel the hot air exhausting.

Thanks for your reply, glad to hear its normal

IF THE HEAT BOTHERS you, get a small ac fan, and put it behind the iMac directed on the spot that is the hottest. It will keep the back comfortably cool to your touch. I need to do this for my portables because they just get too hot otherwise. There just isn't emough surface area to radiate all the heat that is produced by the electronics, and one of them is a 1992 Powerbook 800.

Not knowing what the actual temp cut off is in the machine for the turbo feature to stay on, I will be inclined to do that for my soon to arrive desktop iMac.

You don't need an AC fan as the machine runs cool enough without any additional help. The only time an iMac is going to get real hot is if the vents are clogged with dust or dirt, or, any of the internal cooling fans should fail. Besides, who want to listen to the noise an AC fan makes?

I have a 2011 i7 3.4 iMac. Handbrake will make it warm to the point you cannot even touch the top part without getting burned. It is THAT warm.
I trust that the designers thought about that and that indeed the alu part can act as a giant heatsink. But I still am not comfortable about batch converting dozens of videos sequentially...
I am quite pleased however with the speed of the machine

chscag said:

What you're experiencing is normal. As I stated above, an iMac has three fans. The two you should be concerned with when converting videos is the CPU and hard drive fans. Normal speed for both is around 1200 RPM with a temp of around 35〫to 40〫C. The aluminum back plate acts like a large heat sink and gets warm during any kind of heavy activity.

Put your hand over the top vent when you're converting videos for any length of time and you should feel the hot air exhausting.

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I'm wondering what the temperature cut-off is for the Turbo on the chip in the sandy bridge mid 2011 models not to come one because the imac is too hot.

I actually like the sound of the fan whispering, but since I don't have air and its 95 degrees where I live at the moment, I have to run a fan over all the books that I've owned to keep their temps down.

A small whisper fan at the back placed right over the part that gets really hot when Im using some heavy intensive application is sure better that the three fans in side the imac running wild.

95 degrees and no air? That's torture man! Our Summers here in the Dallas - Fort Worth area of Texas are usually very hot and dry. This year has been especially bad with temps hovering at or near 100 every day. Fortunately, almost everything from our Autos to homes has central air to keep things civilized. I couldn't imagine running our computers without air conditioning.

If you are worried about heat, download an App like SMCFanControl and boost you fan speed when using high CPU/GPU intensive Apps. I boost mine to a Medium setting (about 4000RPM) when using handbrake and then throttle it back when I'm not. No real harm and I do get slightly better performance out of the machines at load.

If you want to batch convert, put a fan blowing on the machine just when you're doing so. You don't have to run the external fan all the time.

I think strategic use of an external fan is better than the internals running super hot.

You could also gut some car stereo amps and bolt their fins onto the back of your iMac. You could call it the CadillaMac :-D

zarathu said:

95 degrees

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An iMac cannot be safely operated at 95F. That is the upper limit of an iMacs operating range per Apple.

I know when I am playing WoW, you can barely touch the back. Seems to run fine and I never hear or feel the fans kick up. /shrug

technologist said:

An iMac cannot be safely operated at 95F. That is the upper limit of an iMacs operating range per Apple.

Click to expand...

I'm sure it is. But that's when you are running it all by itself without any external help. If you blow air across the whole back of the aluminum, then actual temperature will be much lower. I've done it successfully running everything from Wallstreet and G4 Power books, to desktops. I even had an external fan running into the innards of both a MacPlus and a blueberry iMac.

I also use an external fan when doing overnight video encoding. Just a little airflow on the back makes a big difference.