Ive got a 2017 15" MBP with an i7 CPU running Big Sur.

The mac's fan has been running very loud for a few weeks now, i googled it and did an SMC reset, but this has not solved the issue. The fan issue happens pretty much at all times and all work loads.

Ive run the following terminal command sudo powermetrics and got the following result :

Any ideas ?

screenshot of results from terminal command

  • 4
    Is this screenshot with the MacBook running idle? It seems like something is putting load on your CPU. The "CPU Thermal level" should be somewhere around 50 without load. Open Activity Monitor and and make sure you check "All Processes" after clicking "View" in the menu bar. Oct 13, 2021 at 16:26
  • This is pretty much idle, ive got a browser (chorme), mac mail and a few other misc applications running, but nothing heavy like a video, CAD, graphic software etc.. see couple of activity monitor screenshots here : imgur.com/a/4qvfxS8 - it seems chrome is taking allot of resources even though ive only got a <10 tabs open @KevinGrabher
    – sam
    Oct 14, 2021 at 12:11
  • Seems like your Chrome is having an issue, I would start troubleshooting there. Oct 14, 2021 at 16:07
  • @KevinGrabher ive had a look into the chrome browser, using its inbuilt task manager, but couldnt see anything obvious, ive re-checked the activity monitor just now (when the fan is running loud) and it seems my CPU is c. 90% idle, so maybe at the time when i took the original screenshots above chrome was running heavy but was not the root of the issue, see updated screenshot here, any other ideas of what i should look into ? imgur.com/a/pT01ZqV
    – sam
    Oct 17, 2021 at 13:45
  • @KevinGrabher wondered if you had a chance to look at the above ?
    – sam
    Oct 20, 2021 at 14:33

1 Answer 1


Think ive found the issue.

I took the back off the Laptop and the fans were full of dust.

Im not quite sure how they got so dusty, but cleaned them out using a can of air and the laptop fans are running much less now.

  • 1
    Most probably you put your Mac on a smooth surface like on the top of a bed thus increasing the depression on the lateral fans.
    – dan
    Nov 25, 2021 at 19:32

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