MBP 2012 13" 9,2 kernel_task cpu > 300%

Kilobyte Kid

MBP 2012 13" 9,2 kernel_task cpu > 300%



I am new here and forgive my english. I have just bought crucial MX500 2.5 SSD. Installed it. Start ups sometimes stucks halfway and when it fully boots then after some times CPU usage is more than 300% . I have tried reistalling but still no luck. So i am using OLD hard drive now and the high cpu usage system doesnot show up. 

Please help. Thank you.

3 Replies

Re: MBP 2012 13" 9,2 kernel_task cpu > 300%

Did you perform a clean install or did you clone the original drive and if so what method did you use?


What version of OSX/macOS are you using?  Is the drive formatted with APFS or HFS+?  Is FileVault enabled?


My guess is you will need to replace the hard drive cable as this particular laptop is known to have them fail quite often.  Keep in mind your new SSD is capable of transfering data twice as fast as your old hard drive.  


If you have an USB to SATA Adapter/dock/enclosure, then remove the MX500 and try using it externally to see if you have the same issues.  The drive should just boot, but if not you can hold the Option key after power on to access the Boot Picker Menu.  The bootable external drive will show up with an orange icon.  This is a very easy way to prove the cable is at fault and not the cloning process.


Let us know how it goes.

Kilobyte Kid

Re: MBP 2012 13" 9,2 kernel_task cpu > 300%

Thank you for the reply.


I performed a clean install both high sierra and mojave. NO luck . 

I have tried both HFS and APFS. NO luck

I have enabled filevault as well as disabled it. NO luck


CPU usage is still at large (above 80%). It happens even on the old HDD that came with it when i purchased.


Recently i talked to apple support. They couldnot solve the problem. Instead directed me to go to genius bar.

Had an appointment today. In conclusion, genius bar guy said either try installing el capitan or sierra and upgrade HDD to SSD and RAM. I did both still the same. 


I think i figure out the problem but not the solution.

Problem: Whenever i plug in my charger  , in activity monitor the CPU usage spikes. If i unplug it , it goes away and runs normal.

By the way I have two chargers and both chargers are fine because it doesnot have that symptom when i plug it into my 2nd macbook pro. 


Still looking for a solution.




Re: MBP 2012 13" 9,2 kernel_task cpu > 300%

You should open up Activity Monitor located in the Utilities folder and click on the CPU tab and order the "% CPU" column so you can see which process is at fault.  The only thing I could imagine is while on the power adapter the system is running a task which it cannot run while on just battery power so it doesn't drain the battery.  FileVault & Spotlight indexing come to mind as well as system updates, etc.  You can also check the "Disk" tab and see if any sustained disk activity is occurring as well (check the "Data read/sec" & "Data write/sec" in the lower right).


You could perform  SMC & PRAM resets to see if that changes anything, but I'm doubtful.


You could also try running the Apple Hardware Test.  Since you've installed newer versions of OSX, the laptop should include the newer firmware which should allow you to access the diagnostic using Option+D boot option to download & run it from the internet.


If you are able I would also suggest pulling the SSD and booting from it externally to eliminate the possibility of the hard drive cable being at fault.  The hard drive cable on the MBPro 13" (mid 2012) model had a high rate of failure and symptoms could vary widely from power issues to intermittent communication errors.