MacBook Pro mid-2012 Very slow. Kernel_task is using 300%+ CPU

I recently got a new-to-me mid-2012 13” MacBook Pro. It has been slow since I got it. Seems to have a hard time doing the simplest of things. Apps are very slow to load, sometimes the cursor is slow to respond, as well as some lag when typing.

I installed a new 250gb SSD hard drive the other day and re-installed High Sierra. This seemed to only help in the slightest bit. Now it’s barely usable whereas before it was pretty much unusable.

I have a new hard drive cable in the mail, should be arriving tomorrow and I will install that as a soon as it gets here.

I also ran an EtreCheck report this evening to see what that would say. As mentioned, with the computer running so slow I wasn’t able to export the report but I took a few pictures of what looked like the important details.

It indicated that ‘kernel_task’ (which after I looked, seems to be the OS itself) is using 300%+ of the CPU. Now I guess that is why nothing else is working.

Now, what exactly is causing that CPU usage is lost on Me. There is nothing at all installed on the Mac, so I can only assume it’s some sort of hardware issue. Is it possible that the hard drive cable is faulty and is causing this issue? I’m hoping so, as that would be an easy fix. If not, does anyone have any ideas of what the problem could be? Any assistance would be greatly appreciated. Thanks in advance!

Posted on Feb 27, 2018 7:09 PM

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John Galt

Level 10

155,810 points

Posted on Feb 28, 2018 4:46 AM

maestroscherzo wrote:

There is nothing at all installed on the Mac, so I can only assume it’s some sort of hardware issue.

That is correct. A defective hard disk drive cable is certainly among the possible causes.

Please readIf kernel_task is using a large percentage of your Mac CPU - Apple Support as well as the links within it.

A runaway kernel_task can be due to a number of factors, such as:

a failed or disconnected temperature sensor
cooling system inefficiency (an inoperative exhaust fan on Macs so equipped, possibly clogged with dust, including the heat sink)
a worn out, missing, or non-Apple (user-installed) battery on portable Macs
similar hardware-specific causes including internal hardware additions or modifications, external USB and other connected devices, or the driver software required to use them.

Each of those possible causes is equally important and requires its own investigation.

If you can find no other explanation for its behavior, an SMC Reset is justified: Reset the System Management Controller (SMC) on your Mac - Apple Support.

If all else fails Contact Support.

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y_p_w

Level 6

17,762 points

Mar 1, 2018 10:27 AM in response to maestroscherzo

maestroscherzo wrote:

In regards to the difficulty of the tasks, at this point, I am pretty much willing to try anything. Having already disassembled the whole machine, including taking out and reinstalling the logic board, I know I could switch out the trackpad in about 20 minutes. The new trackpad should arrive tomorrow and I am hoping that it solves this problem. At this point, as the AHT is not indicating any additional/other errors, I am a bit more confident in this than my other attempts thus far.

As for the value, I purchased this one at a steal of a deal, and I knew that I may be encountering a problem or two. In my area, used these models of MacBooks are rarely seen for sale under $500.00, so in terms of value, even now I am still quite under that total.

Although I may disagree that I should cut my losses and/or not work on it myself, I do appreciate you all taking the time to reply and give me some ideas on where to go with this. I feel like I'm actually getting somewhere with it now. I will update and let you know how it goes once I install the new trackpad after it arrives. Thanks again!

I personally find the 13" mid-2012 MBP (which I bought new in 2015) to be one of the more desirable models because it's easier to tinker with. The new ones are cool and everything, but there's something to be said for easy to replace memory and drive, along with the optical drive and multiple connections. The new machines don't even perform that much better because there really hasn't been that much of an advance in processor technology. There are also a lot of them with the last one sold new in 2016, so Apple will still have hardware support even though they might not help you out if you've taken apart more than just the drive and memory. There are also a lot of them out there, so salvage parts should be easy to come by for a while.

I personally would feel uncomfortably taking apart the logic board, but a trackpad replacement seems relatively straightforward. Let us know how it turns out.

Mar 2, 2018 9:04 PM in response to y_p_w

Well, the bad left palm temperature sensor is not located in the trackpad or the trackpad flex cable. And, as I have replaced the hard drive cable, therefore I’m going to assume it is not located there either. So, is the only place that it could be is on the logic board? If anyone has ANY other ideas or suggestions, please let me know, otherwise I’ll be ordering a new logic board. And if that’s the case, and the sensor is not on there... well, that would not be good. I am not worried about any warranties, if the Apple people won’t work on it, etc. Just looking for suggestions/ideas of where the sensor is. Thanks again.

John Galt

Level 10

155,810 points

Mar 1, 2018 8:31 AM in response to maestroscherzo

Even if you don't succeed in fixing that Mac, the education you're getting is worth the investment.

John Galt

Level 10

155,810 points

Mar 22, 2018 6:47 PM in response to maestroscherzo

Great! Thanks for the update.

Feb 28, 2018 7:46 PM in response to etresoft

I am not worried about the new SSD, I am not convinced that has anything to do with what’s going on, as this problem existed with the original HDD.

As for having only Apple techs work on it, that would be great. But if I had that kind of money, I would have bought a new machine. That being said, other than with a previous owner, the only thing I had done was the hard drive, and I re-did that myself today when I replaced the Hard Drive cable. I’m not afraid to get in there and take it apart, I don’t have much to lose at this point.

I actually just finished disassembling and re-assembling the machine. I took out the logic board and re applied thermal compound on the heat sync. I also double checked all the connections, everything appears to be good.

I disconnected the trackpad, as I read that there was a temp sensor in there and tried running it to see if that was the problem. Same symptoms were occurring when trackpad was unplugged.

I am now running the Apple Hardware Test to see if it will give me any more info, will post the results when it’s completed.

I do not think that the MacBook is overheating, I am pretty sure it just ‘thinks’ it is. Will the only option be to replace the whole logic board? Or is there a way to bypass this? I realize that if there is, I assume any sort of responsibility if something goes wrong. I am also a bit concerned that even if I replace the logic board that this issue will continue. Returning it is not an option. Thanks again for the replies.

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MacBook Pro mid-2012 Very slow. Kernel_task is using 300%+ CPU