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Retina MacBook- CPU overload, fan noise

ThisBougieLife

ThisBougieLife

Suspended
Original poster
Jan 21, 2016
3,259
10,666
Northern California
Just this morning I had a strange problem on my Retina MacBook (13-inch, 2012 model) that I've never had happen before. All of a sudden, a minute or so after starting up the computer, the fans started revving at full speed and I could hardly move the arrow around.

I went into the Activity Monitor and at one point it showed "kernel task" at 607% CPU usage. After a while it stopped (no programs open at the time) but then it started up again randomly. What is going on? (I was even able to restart the computer during this "overload", but it persisted through the restart. The only thing that stopped it was shutting it down, but then when I started up the laptop again, it happened again).

This really sucks because I was planning on selling this computer (obviously can't now) and I haven't backed up my stuff in a while and I was planning on doing that before selling (and I don't think that's going to be possible now unless I fix this). Any help is appreciated.
 
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Yes, I know, I suck, and I've accepted that. But I actually seem to be able to backup through this mess. The fan is still revving and the arrow is hardly moving but it's actually successfully copying my files to the external HDD (much of my stuff is on the cloud so it doesn't matter anyway, but some of it is on the SSD). After this I will run Apple diagnostics.
 
Well I ran the diagnostic test and it said "no trouble found" and the problem doesn't seem to be happening now.

Don't know what to make of it--no telling if it might just happen again. Since it originally happened as soon as I started up the computer (and now it's not), it doesn't seem to have anything to do with any program I have.
 
So, you have a three-year old laptop, and you experience some strange effect - first time in 3 years, and now you feel ready to chuck it out entirely?

The "problem" may simply have been a one-time glitch in the hardware. Likely a simple SMC reset took care of the issue.
You might never see it again.
Your hardware test passed.
You COULD try a simple reinstall of OS X (booting from your Recovery system), which will check during the reinstall that all parts of the system files are where they are supposed to be, and that all are installed properly.

SMC reset:
  1. Shut down the Mac.
  2. Plug in the MagSafe power adapter to a power source and to your Mac.
  3. Using the built-in keyboard, press Shift-Control-Option on the left side of the keyboard, then press the power button at the same time.
  4. Release all keys, then press the power button again to turn on your Mac
Click to expand...
Also, do PRAM reset during the boot.
Immediately press and hold Option-Command-P and R keys. You should hear the boot chime sound.
Keep holding the same 4 keys until you hear the boot chime 2 more times, then release the keys to let your MBPro boot normally.
After those resets, be sure to check that you boot drive is set as the default in your System Preferences/Startup Disk pane.
 
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ThisBougieLife said:
Can anyone at least tell me what this problem was?
Click to expand...

Not withou more information.

Will it happen again?
Click to expand...

Maybe? I wouldn't worry about it. If it does happen again you could do more in depth troubleshooting. Try reinstalling OSX as someone else suggested.

Is the laptop garbage or could I potentially sell it?
Click to expand...

If you want to sell it, go ahead.
 
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What the problem seemed similar to is when a computer overheats. My friend's MacBook overheated one time and the same thing happened: fans revved at super speed and the computer was really slow. But that time it was so hot you couldn't even touch it. In my case, the laptop wasn't actually getting hot, but it was mimicking the effects of an overheating.

DeltaMac said:
So, you have a three-year old laptop, and you experience some strange effect - first time in 3 years, and now you feel ready to chuck it out entirely?
Click to expand...

See the first post. I was already planning on selling it. The reason why this is an issue is I don't want to sell someone a defective computer. And there was no reason for me to think it was defective until this problem happened because nothing like that has ever happened to me before. The worst problem I had over the past 3 years was occasionally a program crashed. That's it. I've never had to repair this computer or anything. Now this happens and it made me think maybe something more serious was wrong.

I did decide to reinstall OS X after all. The computer seems to be working fine right now. I hope it doesn't happen again.
 
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Then, you can be a good joe, and disclose to a potential buyer that you aren't sure about the hardware, and that the system will need to be reinstalled.
If the hardware passes a hardware test/Diagnostics, then an OS X reinstall is your next Good Thing™.
If you are preparing to sell, then a drive erase, and clean install of OS X, with no user setup, is more good stuff.

Might be another good step if you use some system monitor software for a few days, and watch for high temps, or high current draw. If you don't see anything unusual in normal use for you, you might be more encouraged that you had a one-time event, some sort of glitch. I use HWMonitors for that, but there's others.
 
So just an update: It happened again, the "seizure" as I call it. Even despite the clean install, it happened almost as soon as I started up the computer for the first time tonight. This "seizure" lasted about 20 minutes. After it subsided, I was able to install HWSensors. There was literally nothing different on HWSensors between the "seizure" period and the normal period other than the fan speed.
 
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My first idea was: 3 years old = may have muck and dust accumulated in and around the cooling system. But you should have seen a temperature hike on HWSensors, thus not so likely. You could still open the machine and see if there's much dust inside, just to make sure (disclaimer: I'm not responsible for any damage you may cause by doing so!).

My next thought was some loose solder connection, as the problem seems to be gone after the machine is heated up.

Did you reset SMC and PRAM as suggested above?

And as I'm no native speaker, please bear with me, but I'm not sure if I understood your last post correctly: You installed HWSensors _after_ the "seizure" and say there was nothing different. Did you have yet another "seizure" _after_ you installed HWSensors?
 
Yes, sorry, I wasn't clear about that. It happened again after I installed HWSensors. Then it stopped and didn't happen for the next three hours (I had the laptop on for three hours, using it, until I went to bed and it didn't happen in all that time). But then this morning I turn on the computer and it happens almost immediately.

I didn't do the reset thing, but I'll try that.
[doublepost=1457974363][/doublepost]Just did both resets, SMC and PRAM. Problem still happens. This time it actually started happening while the Apple logo was displayed, before the log-in screen even appeared.

I'm guessing the motherboard's failed?
 
If it is "failing" almost immediately, then you should get a definite failure now in your hardware test.
The hardware test has both a standard, and extended testing routines. Be sure to run both, as the results can be different.
 
Could it be the indexing service? Had the same symptoms on a MBA caused by indexing service after changing a bunch of files.
 
A faulty temp sensor will send the fans into overdrive. Since the computer doesn't know how hot it is, it goes "well, better safe than sorry!" and goes full blast.

Are you getting any weird temp readings?
 
ThisBougieLife said:
But then this morning I turn on the computer and it happens almost immediately.
Click to expand...
It more and more sounds like some hardware issue to me, occurring more often (if not nearly always) with a cold system and going away when the system is heated. A faulty temperature sensor with erratic behavior, especially on a cold machine, would fit to the symptoms you describe, but it would not explain the massive lagginess during those fan alarms. Unless it's the CPU-internal sensor, causing the CPU to massively down clock as self protection.

If the Apple Hardware Test does not show any problems already, you could (try to) check for any strange or suspicious readings (e.g. very low CPU clock) with Intel's Power Gadget (https://software.intel.com/en-us/articles/intel-power-gadget-20).

Perhaps you could also check the (SMART) status of the internal hard drive: if that is dying, it might explain both the high fan rpm and the system lagginess.
 
How do I check the SMART status of the internal hard drive?

I'll try the Power Gadget thing, though. But yeah, I ran the hardware test again (including the extended one) and it showed no problems. Of course the fans were not revving during that whole time and now I'm using the computer just fine with no issues. It does seem to correspond with first turning the computer on, though. For example, I don't picture it happening again for the rest of the day (I'll post again if it does), but tomorrow when I go to turn it on after having shut it down, I'm sure it will do it again.
 
Neodym said:
It more and more sounds like some hardware issue to me, occurring more often (if not nearly always) with a cold system and going away when the system is heated. A faulty temperature sensor with erratic behavior, especially on a cold machine, would fit to the symptoms you describe, but it would not explain the massive lagginess during those fan alarms. Unless it's the CPU-internal sensor, causing the CPU to massively down clock as self protection.

If the Apple Hardware Test does not show any problems already, you could (try to) check for any strange or suspicious readings (e.g. very low CPU clock) with Intel's Power Gadget (https://software.intel.com/en-us/articles/intel-power-gadget-20).

Perhaps you could also check the (SMART) status of the internal hard drive: if that is dying, it might explain both the high fan rpm and the system lagginess.
Click to expand...

I believe OS X throttles the CPU when the temperature of the machine gets too hot. A faulty temperature sensor would certainly explain the fans going into overdrive and the machine slowing down due to thermal throttling.
 
ThisBougieLife said:
How do I check the SMART status of the internal hard drive?
Click to expand...
The OSX Diskutil(ity) offers the current SMART status (see here). If you want to check more in-depth, you have to use some 3rd party tool like e.g. SMART Reporter, but if that does not run on El Cap anymore, you may have to pay for a tool in the Mac App Store (or google around a bit).

ThisBougieLife said:
For example, I don't picture it happening again for the rest of the day (I'll post again if it does), but tomorrow when I go to turn it on after having shut it down, I'm sure it will do it again.
Click to expand...
If that would be true, I'd consider that close to proof of a cold solder connection / damaged temp sensor / damaged motherboard.

DarkSel said:
I believe OS X throttles the CPU when the temperature of the machine gets too hot. A faulty temperature sensor would certainly explain the fans going into overdrive and the machine slowing down due to thermal throttling.
Click to expand...
AFAIK there is an additional emergency throttling inside the CPU itself. But it would fit the picture nevertheless: On cold start the fans revv up to max in order to protect the hardware, so it takes some time until the hardware has reached operating temperature, which closes a probable hair crack and the hardware behaves normal again.

Daring natures have "baked" their hardware in the past to solve solder-/hair crack-related problems, but in this case I'd say it'd be best to see an Apple Genius and have the machine checked with the enhanced tools available there. They will probably recommend a motherboard replacement as only possible option.

Alternatively OP could try to tolerate the fan noise during startup and/or experiment with keeping the computer on operating temperature by keeping it running instead of shutting down, perhaps a "light" sleep with Power Nap on or something. However this will probably only procrastinate until the sensor ultimately fails.
 
My hypothesis was correct. I used the computer all last night and the "seizure" didn't happen.

This morning, the laptop was physically cold, I started it up and immediately the fans started revving like crazy. It's off now, and if I start it up later today after I get home from school and it doesn't do it, then I'll know it's because of the temp sensor.
 
Okay, some updates. One thing I was able to pick up on is that, by using the Activity monitor, I've found that when these "seizures" happen, the System load at the bottom spikes to about 86%, even though I have no programs open and I'm not even doing anything. No unusual process comes up under the "CPU" or "Memory" tab to cause this happen--it just happens randomly while the computer is idling. The spike in this screenshot I took represents when the "problem" happened:

14aycyt.png
 
Curious.
Is there a spike at that same time in memory pressure, too?
Check that the lists are set to show All Processes, and not just My Processes.
You can also check under Energy, although energy is not always a simple one to interpret the report there.
 
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