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Retina iMac noise

O

omenatarhuri

macrumors 6502a
Original poster
Feb 9, 2010
902
844
Hey,

Some reviews seem to mention that the retina iMac is usually quiet, but the fans can 'definitely be heard' when they kick in.

Please share some experiences on the topic if you have received you retina iMac and have done some heavy computing like a long export, rendering or gaming on it. Something that really puts the system to its limits continuously for hours (or at least 30 mins).

I'd be especially interested to hear from those with the i7 processors and 295x GPU. Also any experiences regarding 1TB fusion drive noise is welcome.
 
thagomizer

thagomizer

macrumors 6502
May 26, 2005
298
6
USA
I've had my Retina iMac 27" 4GHz M295X with 1TB fusion drive running for about 8 hours now, and the fan is on constantly. It's a definite whir or hiss, sounds like white noise, and smcfancontrol reports it's 2160rpm. The CPU is 102 degrees F.

Is this normal? If I quit smcfancontrol, the fan is still running at the same speed. It's about as loud as a 13" MacBook Pro's fan at full blast, that's the only thing I can subjectively compare it to.

I checked Activity Monitor, and the computer isn't doing anything.

I did put in an extra 16GB of Crucial RAM, for a total of 24GB. The RAM shows up, so I'm sure I installed it properly.

----------

I rebooted it, and the fan noise was on constantly throughout.

So I shut down, started up again, and the fan noise started only when it reached the desktop. Still just as loud. Now 111 degrees, 2162 rpm.
 
8CoreWhore

8CoreWhore

macrumors 68030
Jan 17, 2008
2,653
1,191
Tejas
thagomizer said:
I've had my Retina iMac 27" 4GHz M295X with 1TB fusion drive running for about 8 hours now, and the fan is on constantly. It's a definite whir or hiss, sounds like white noise, and smcfancontrol reports it's 2160rpm. The CPU is 102 degrees F.

Is this normal? If I quit smcfancontrol, the fan is still running at the same speed. It's about as loud as a 13" MacBook Pro's fan at full blast, that's the only thing I can subjectively compare it to.

I checked Activity Monitor, and the computer isn't doing anything.

I did put in an extra 16GB of Crucial RAM, for a total of 24GB. The RAM shows up, so I'm sure I installed it properly.

----------

I rebooted it, and the fan noise was on constantly throughout.

So I shut down, started up again, and the fan noise started only when it reached the desktop. Still just as loud. Now 111 degrees, 2162 rpm.
Click to expand...

What I don't understand is why your fans would be so loud while running at their low, idle, speed. My rMBP is silent at that speed, and at only 85F with general use.

Try another app to see fan speed. I wonder if they are actually going faster than SMC suggests. Try iStat Menu free trial and see.
http://bjango.com/mac/istatmenus/
 
thagomizer

thagomizer

macrumors 6502
May 26, 2005
298
6
USA
Wow, that's a really nice application. Ok, iStatMenu shows exactly the same fan speed as the smcfancontrol menu. But it's pretty loud at 2160 RPM right now.

I took out the Crucial RAM, by the way. Made no difference to the fan.

----------

It's getting louder! I can hear it across the room. In back i put my hand and I can feel air coming out, slightly warm. Not hot at all.
 
thagomizer

thagomizer

macrumors 6502
May 26, 2005
298
6
USA
Retina iMac owners please respond

Retina iMac owners, what is your fan speed when the computer is doing nothing? Would you please measure with one of the aforementioned programs and post here. 2100rpm may be normal for a laptop but it seems high for a large desktop fan. I've seen pictures in the iFixit tear down, it's huge.
 
redheeler

redheeler

macrumors G3
Oct 17, 2014
8,419
8,841
Colorado, USA
Yeah, that's definitely not normal. Mine hovers around 1200 rpm on idol (in smcFanControl). It's barley discernible if I'm not doing something CPU intensive, although when I am I definitely hear it kick in. I also have 16 GB Crucial RAM installed, by the way, although I doubt that has anything to do with it.
 
W

WilliamG

macrumors G3
Mar 29, 2008
9,923
3,800
Seattle
thagomizer said:
Wow, that's a really nice application. Ok, iStatMenu shows exactly the same fan speed as the smcfancontrol menu. But it's pretty loud at 2160 RPM right now.

I took out the Crucial RAM, by the way. Made no difference to the fan.

----------

It's getting louder! I can hear it across the room. In back i put my hand and I can feel air coming out, slightly warm. Not hot at all.
Click to expand...

redheeler said:
Yeah, that's definitely not normal. Mine hovers around 1200 rpm on idol (in smcFanControl). It's barley discernible if I'm not doing something CPU intensive, although when I am I definitely hear it kick in. I also have 16 GB Crucial RAM installed, by the way, although I doubt that has anything to do with it.
Click to expand...

1200rpm sounds right. My 2012 27" iMac idles at between 1192-1208 depending on what iStat Menus is reporting. So 1200rpm is probably the aimed speed, which varies +- % points of rotations. 2160 is what it would be under load. I'd suggest resetting SMC/PRAM and see if that helps, before calling Apple.
 
thagomizer

thagomizer

macrumors 6502
May 26, 2005
298
6
USA
I tried SMC reset several times to no avail. So I did a complete wipe and reinstall of Yosemite using a thumb drive installer. Now, computer is completely silent even with the extra memory back in. So the problem was some software I had (I brought everything over from an external backup using migration assistant).

So now I just need to figure out which of the software I've accumulated over the past 13 years of OS X is causing my fan to run up.
 
B

bp1000

macrumors 65816
Jul 7, 2011
1,476
185
I had trouble with my iMac last winter. I got through about 4 before settling on a unit which still had noise.

2 I tried had a definite fan whir like noisy bearings the other 2 had a slight crackle when the screen brightness was below 4 bars and there is a dark background on the screen.

Delving into the reason for this noise it seems iMacs have always suffered from screen crackle or fan hum. Seems the retina iMac is not exempt.

Be aware that not all ears can detect these noises and low abient noise also amplifies the issue.
 
T

trims

macrumors regular
May 11, 2011
232
79
Nottingham, UK
thagomizer said:
Wow, that's a really nice application. Ok, iStatMenu shows exactly the same fan speed as the smcfancontrol menu. But it's pretty loud at 2160 RPM right now.

I took out the Crucial RAM, by the way. Made no difference to the fan.

----------

It's getting louder! I can hear it across the room. In back i put my hand and I can feel air coming out, slightly warm. Not hot at all.
Click to expand...

Is this not the standard new computer behaviour - indexing files / backing up etc?? Leave it for a day or two and maybe things will settle down?
 
thagomizer

thagomizer

macrumors 6502
May 26, 2005
298
6
USA
I did a second restore from migration assistant, rebuilt permissions, and deleted smcFanControl. Not sure which of those did the trick, but the noise has not come back. Maybe something went wrong in the first migration.

iStatMenu shows fan speed as 1196. Much better. Thanks everyone for your suggestions.
 
xgman

xgman

macrumors 603
Aug 6, 2007
5,672
1,378
thagomizer said:
I've had my Retina iMac 27" 4GHz M295X with 1TB fusion drive running for about 8 hours now, and the fan is on constantly.

----------

I rebooted it, and the fan noise was on constantly throughout.

So I shut down, started up again, and the fan noise started only when it reached the desktop. Still just as loud. Now 111 degrees, 2162 rpm.
Click to expand...

Same exact config here except I have a 1TB SSD, but same problem as I already stated. I suspect it is the 4ghz processor that is heating things up.

----------
thagomizer said:
I did a second restore from migration assistant, rebuilt permissions, and deleted smcFanControl. Not sure which of those did the trick, but the noise has not come back. Maybe something went wrong in the first migration.

iStatMenu shows fan speed as 1196. Much better. Thanks everyone for your suggestions.
Click to expand...

Could something have been going on like long spotlight re-indexing or TM etc? If so, it might spin up again at some point.
 
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