I have a 2011 Macbook Pro 15" running Sierra.

The Macbook's fans are annoying me to no end - they are running most of the time I do serious work, right from the minute I start. It can get hot here in the summer, but it happens also at reasonable room temperatures, like right now, at 23°C (73°F).

Here's a graph of my CPU load over an extended period of time, looking fairly relaxed to my eyes:

enter image description here

yet the fan is running constantly:

enter image description here

This has been happening for the past three versions of OS X, so it's nothing version specific. (I started thinking that maybe this isn't normal only recently.)

Things I have tried:

  • Made sure there are no processes running in activity monitor that hog a lot of CPU time (my work tends to be CPU/GPU intensive though, Photoshop, IDEs, etc. open in parallel all the time)
  • Reset NVRAM and SMC, many times
  • Opened the device and removed a giant piece of lint from behind the air ducts (I was sure that'd fix it):

    enter image description here

    (I didn't do anything else in there other than remove the easily accessible, obvious blockage, though)

Is this normal? Is there anything I can do? Is there some unofficial way to get to the CPU, and maybe apply some better thermal paste? Is there some other potential bottleneck that I should look at other than CPU?

The machine is perfectly usable for me otherwise despite its age (after a RAM and SSD upgrade).


You need to strip & clean the entire airflow, if that fluff-ball was clogged in the outlet, there's an entire duvet inside. All the machines here get a full strip & clean once a year, with a 'quick blow round' in between. If it's gone 6 years without cleaning, it's likely to be pretty well-insulated in there by now.

iFixit teardowns are second to none - there is far too much for me to try to précis here
iFixit - MacBook Pro 15" Unibody Early 2011 Teardown

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    Yup - this did wonders. Opened it again, cleaned the fans themselves (they had a crispy crust of dust that I had to actually scratch off with a screwdriver) and blew through the ducts with one of those compressed air cans. The fans run much more silently now and at about 2000 RPM less than they did before at comparable CPU temps. – Pekka Jan 29 '17 at 15:46

Open Activity Monitor and take screen shots of the full window to share with us. I'd like to see the CPU tab, sorted by % CPU with the arrow pointing down; and the ENERGY tab, sorted by Avg Energy Impact with the arrow pointing down.

These can help us find out if you have a run-away app or process.

After taking those screenshots, I'd advise performing a Safe Boot. Give it a few minutes of runtime, long enough for you to determine if it's better in Safe Boot or not, then restart to get back out of Safe Boot.

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