I'm new user of a brand new 15" Mid 2015 MacBook Pro (i7 processor), which I got about a month ago. I've been having problems with performance.

Every time I try to do anything more CPU consuming than browsing the internet (for example opening a project in IntelliJ or compiling a Java project), my Mac becomes extremely slow.

I noticed that CPU is working on 800 MHz frequency but CPU temperature is low. Fans stay quiet all the time (~2000 rpms). When I need power from my CPU it slows down, but I don't think it should.

I also tried live USB Ubuntu and I simulated some load and the result was the same, you can see it on the screen. ubuntu temps

I also tried SMC reset but no result. Does it look like hardware failure?

Example of Activity monitor processes listing while throttling below. After longer build Idle is almost 0%, temperature is okay, frequency is 800MHz. Process kernel_task is sometimes using much more CPU enter image description here

  • What does Activity monitor say?
    – Allan
    Commented Jan 10, 2017 at 22:17
  • I added screen from Activity monitor to my post.
    – djagielo
    Commented Jan 11, 2017 at 7:53

1 Answer 1


In my case opening MacBook and cleaning it from dust helped reduce throttling from 800Mhz to 1600MHz which is still not advertised speed , but at least twice as better :) Also I've noticed that in my case such throttling occured only with external monitor and external GPU. You can use gfxCardStatus to monitor which GPU and which processes require external GPU.

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