CPU utilization low, system hot, fans loud

My Mid 2011 27 iMac has been running well. Here's the basics.

The system has an SSD rather than a hard disk drive (so should be less heat than normal there). I use the system for development: it does not and never has had a lot of junk on it. About four weeks ago the system started to run hot and the fan was loud while the CPU is around 99% idle. I did download the trial of TG Pro and the CPU seems

The "load" pictured below, which is under 3%, is elevated from normal baseline because I am running TG Pro and Activity Monitor.

The noise is very annoying and seems way out of line for the system load.

Does anyone have practical suggestions or see any obvious problems? (Before you point out 24GB of RAM and other basic issues, keep in mind that this system has been stable and performing normally in current configuration for about nine months, save El Capitan updates).

iMac, OS X El Capitan (10.11.4), Fan

Posted on May 6, 2016 11:31 AM

19 replies

SeaPapp

Level 7

26,492 points

May 7, 2016 1:12 PM in response to eezis

eezis wrote:

But the app has not been running. It was only installed to investigate this problem. I start it, take the screenshot, close it. And I will delete it as soon as I don't need it. It doesn't auto start and is not part of the normal environment.

Well no.....that's not how fan control software works. When you install it it runs all the time.

eezis Author

Level 1

8 points

May 7, 2016 1:29 PM in response to SeaPapp

MIke, I just opened activity monitor and sorted by name. The process is not running. I started the app, the process appeared. I closed the app, the process disappeared. For this app -- TG Pro -- to run in the background you need to specifically set that option in the preferences. This app has only been on my machine for about 25 hours. It's total runtime over the life of my system is probably under 30 minutes. The problem has existed for weeks and predates this application that is not even running.

SeaPapp

Level 7

26,492 points

May 7, 2016 1:37 PM in response to eezis

Just leave it set on System ok?

eezis Author

Level 1

8 points

May 7, 2016 1:38 PM in response to SeaPapp

Already done per prior message.

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CPU utilization low, system hot, fans loud