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Treeman574

macrumors regular
Original poster
Feb 5, 2011
123
0
QLD, Australia
Just today I noticed my 2011 2.0ghz mbp had particularly terrible battery life. Upon further inspection there is a kernal_task using 78 threads and just under 5% cpu.

Now with brightness at about 33% and only pages / numbers open. My fully charged battery lasts only 2hrs. (wifi off)

Is there any way to fix this problem or should this task finish with time?


(Even at the time of typing the battery has dropped 5%.)
 
That's normal for kernel_task to use 5%. You must have something else going on to cause your problem.
 
After running through another battery, the task has reduced to 1% and my battery life has returned to normal.

Also forgot to mention running snow leopard, and the cpu was hitting 85C. Must have been some important system task.
 
Just today I noticed my 2011 2.0ghz mbp had particularly terrible battery life. Upon further inspection there is a kernal_task using 78 threads and just under 5% cpu.

Now with brightness at about 33% and only pages / numbers open. My fully charged battery lasts only 2hrs. (wifi off)

The kernel_task is the part of Mac OS X, which controls your hardware and your software. Your problem sounds like a problem with the GPU. Disable the more powerful GPU in the Energy Saver preferences and your Mac should run much cooler!

If you use Lion, then it is "normal" that it requires more power, because the GUI related code runs 75 percent slower than the Snow Leopard GUI code (likely a OpenGL/OpenCL problem in Lion). Snow Leopard had a similar problem, regarding some games. They fixed this problem in Snow Leopard 10.6.4, IIRC.
 
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