Random high cpu. Tried everything I can think of.

[UrsaMinor]

Late 2011 15" Macbook Pro. The Macbook Air runs High Sierra. I installed an SSD in it about 1 1/2 years ago.

Various programs will randomly cause the CPU to spike and begin heating up. This is followed by a black screen and a thermal shutdown. This problem began suddenly.

What I've found and tried:

Noted the issue occurs even when booting to a High Sierra USB stick. This would indicate a hardware issue and not a software issue.

Reset the SMC. Issue remains.

Toggled automatic graphics switching. Issue remains.

Tried Safe Mode. Issue remains.

Opened the Macbook. Both fans run and the cooling system is clean.

Disconnected the battery. Issue remains.

Performed Apple’s quick and extended hardware test. The hardware passed.

Re-installed High Sierra. Issue remains.



At this point, I'm calling it a CPU or logic board component failure despite the hardware passing. Do you agree?

 

[chabig]

That sounds like a reasonable assessment.

 

[UrsaMinor]

Thanks for the reply chabig.


Given that the Macbook is around 10 years old, I have to decide whether or not to get the owner to send the laptop to a shop that's 2 hours away and does board level repair, or suggest she replace the Macbook.

 

[chabig]

For some reason the CPU isn't being cooled as it should. The fix might be as easy as reapplying thermal paste. But then again, a ten year old machine just won't perform like a new one. My wife still runs a 2010 MacBook Pro, but doesn't use it very much. If it were mine, it would drive me crazy due to its speed. Your friend could get a new MacBook Air for about $1000 and it would be worth it, in my opinion.

 

[UrsaMinor]

Yes, I'm leaning toward the replacement suggestion.

It's not the thermal paste, as it began suddenly, and the cpu spikes occur randomly. It's an intermittent cpu issue, or an intermittent component problem on the logic board.

Also, it's actually quite fast since I replaced the clunky mechanical drive with a SSD.

 

[Audit13]

This MacBook also has a GPU problem that is now well known.

Perhaps this is adding to any existing issues.

Even with a failing GPU, the MacBook can pass the Apple diagnostic routine.

 

[UrsaMinor]

Yes, to be more specific, I suspected a Radeon GPU issue, and that's why I tried disabling the automatic graphics switching. Hmm. I've got nothing to lose, so I'm going to try a program I came across a few months ago called GFX Card Status that disables the Mac from using the Radeon and instead use Intel graphics exclusively.

 

[UrsaMinor]

No luck with GFX. The issue occurs on both the Intel and Radeon graphics. Logic board problem indeed.

 

[motulist]

If you've got it open anyway, might as well try blowing the whole thing out with compressed air.

 

[UrsaMinor]

Thank you for the suggesttion motulist, but it's not a cooling system problem.

 

[motulist]

Thank you for the suggesttion motulist, but it's not a cooling system problem.

I've found compressed air to be in the same category as "just hit it a couple of times". Meaning it usually doesn't work, never causes a problem, and occasionally fixes problems for no explicable reason.

 

[UrsaMinor]

Ok, I blew it out anyway . It was clean as a whistle. Then again, when I installed the SSD about a year ago, I blew out the cooling system as I always do, and almost nothing came out.