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Level 1

6 points

iMac 5K Retina Display Late 2015 fan at idle?

I recently got my iMac 5K Retina delivered and after I installed it I noticed that in my quiet room with fans spinning at the standard 1200rpm, I can still hear the fans even sitting about 30-40cm/15 inches away from the display. When I bring my ear to the bottom of the iMac it becomes more evident, when i expected it to be completely silent unless I'm running heavy apps. It's not a loud fan noise, rather air blowing out from the back and bottom of the iMac and in a room with medium noise or traffic rushing outside, you won't be able to hear it, but since my room is quiet, it really distracts me because my rMBP is usually silent. The sound is like that sound that you know a computer is running in the room if you were to step inside a room blindfolded.

Is this normal? I ran diagnostics and everything checked out fine.

Thanks!

iMac (Retina 5K, 27-inch, Late 2015), OS X El Capitan (10.11.1)

Posted on Oct 28, 2015 12:52 AM

29 replies

dialabrain

Level 10

122,591 points

Jan 7, 2016 1:41 AM in response to Jhua8

There are a few possibilities. Some people might be sensitive to the frequency the fan makes rather than its volume. It is possible of the thousands of units they make some units may have fans that are noisier than others. It could be an assembly issue. What I know is mine is extremely quiet as I've mentioned elsewhere.

For me to hear the fan at idle, none of my drives can be on and I have to have my ear right next to the cooling slot at the bottom of the unit.

Jan 20, 2016 3:33 AM in response to dialabrain

Just another thought on this: Recently, I have throttled my iMac's fan down to 800 rpm. Now, my experience is the same as dialabrain's: I have to have my ear quite close to the machine to hear anything from it in a quite quiet room (internal temperatures remain reasonable, by the way).

The varying descriptions here make me wonder whether maybe Apple sets the fan to different idle rpms depending of the CPU and GPU built into the machine. My configuration is almost high-end (i7 4.0 GHz CPU and AMD Radeon R9 M390 GPU), so maybe that's why it idles at 1200 rpm by default.

saholz

Level 1

42 points

Jan 20, 2016 6:20 AM in response to Marius_66

I just picked up my new 27" iMac last Friday. It has been completely silent, with no trace of fan noise that either I nor my wife can hear. The sound of my breathing is louder than this machine.

Jan 20, 2016 6:23 AM in response to saholz

Fine. Considering my earlier remarks: Which processor and CPU does it have?

saholz

Level 1

42 points

Jan 20, 2016 6:38 AM in response to Marius_66

It has the I5 3.3 processor and 2TB Fusion drive.

dialabrain

Level 10

122,591 points

Jan 20, 2016 6:39 AM in response to Marius_66

FWIW, mine has a 4 GHz Intel Core i7 CPU and a AMD Radeon R9 M395X 4096 MB GPU. I'm not using fan control software.

saholz

Level 1

42 points

Jan 20, 2016 7:07 AM in response to dialabrain

Forgot to mention ... I have the AMD R9 M395 with 2GB.

Feb 25, 2016 1:46 AM in response to dialabrain

I have the same problem with my iMac 5K with 4 GHz Intel Core i7 CPU and a AMD Radeon R9 M395X 4096 MB GPU.

as you have solved your problem?

What do you think is the arrangement?

dialabrain

Level 10

122,591 points

Feb 25, 2016 3:17 AM in response to RicardoBencomo

RicardoBencomo wrote:

I have the same problem with my iMac 5K with 4 GHz Intel Core i7 CPU and a AMD Radeon R9 M395X 4096 MB GPU.

as you have solved your problem?

What do you think is the arrangement?

I've never had the problem. Mine has always been nearly silent.