Huge CPU spike ONLY when MAC plugged into power source?!

Morning folks,

I'm getting into the final mixing phase of a current project.  I've been experiencing a very perplexing issue.   After all my troubleshooting I still am unsure as to the cause. 

In my sessions, with all plugins enabled, my CPU usage normally hovers comfortably between 35 and 45 percent (on the live meter) comfortably.  I don't notice audio dropouts unless I'm doing heavy automation during the session - everything performs as expected.
Recently though, my session will run just fine for about 5-10 minutes and then suddenly my CPU usage will spike to 150-160  percent and my session will just grind to a halt and I'm unable to continue.  I've literally just sat and watched this happen without anything changing in the session.  
In looking at my Mac's activity monitor I notice that both live and my Kernal_task shoot up in CPU usage during these times.  
At this point, not just the session but my entire computer becomes extremely sluggish and I'm unable to do much at all.  During this time I have tried freezing all tracks with no improvement.  I've also disabled all plugins and have increased my buffer to the maximum - nothing seems to correct the issue.
After troubleshooting, I noticed this issue ONLY occurs when my MAC is plugged into a power source!  It NEVER occurs when operating from my battery.  In my sessions, during a spike, if I unplug my power source the session will drop back to 35-45 percent usage within 5-10 seconds!  In further testing I can actually stop and start the problem by plugging and unplugging my power source.  I have tested the issue with the cable that came with my MAC and a brand new one I bought.  The issue occurs with and without my audio interface plugged in.
I could understand why this would occur when my computer was UNPLUGGED, but I'm unsure why it would occur when LIVE is drawing power from the power source - any ideas?
Here is some information about my machine:
Macbook Pro 15 inch (late 2011)
2.2 GhZ Intel Core i7
8 GB 1333 DDR3
Any help would be incredibly appreciated - I'm on a deadline and am getting nervous :(


antchar 2 years ago | 0 comments

1 answer

  • Lost069
    5 answers
    4 votes received
    1 vote

    Sounds like some thing running in the OS back Ground that go's in to power save when your on battery power. Time Machine could be your problem.  

    2 years ago | 0 comments

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