Skip to main content

The March 2015 update of Apple's 13" MacBook Air features fifth generation Intel Core i5 and i7 processors, resulting in slightly increased performance and battery life.

630 Questions View all

I have an MacBook Air 2015. Cpu usage 100%

Macbook Air 2015 was super slow so I installed Ubuntu on it. When i am opening any applications or playing video cpu usage is 100% perhaps ram usage is just 1.4/8 GB.

What could be problematic here? I tried running it without batteries also. No success.

Answer this question I have this problem too

Is this a good question?

Score 0


Why not installing macOS again and try to find the issue?


You will need to re-install macOS on your system to figure out the hardware aspects.

As far as Ubuntu you will need to check the build you used and any required patches.


@inwerp - You didn't to the homework!

BenZ78 and my supportive comment did before you answered technically is a duplicate and drags the OP down a rabbit hole you created before getting the results of the diagnostic process!

Don't be so quick! Our goal here is two fold: Get people to fix their systems and educate on the proper diagnostic process to know the direction is correct. Sometimes you just need to wait to get the data to get to the next step.

You have skills! You just need to hold things back a bit! And don't rush in when others have asked the OP for a diagnostic process to get whats needed. Be supportive and if you've seen another condition which could also be the fault I do encourage you to state it! But likewise don't blast people for stating the same on your post. Take a breath and think!


@danj Please do not delete this comment.

you have abolutely no right to delete my comments. they do not violate any rule of this website, they are technically correct and provide possible solutions based on my experience as full-time mac repair tech.


@inwerp - As a monitor of the Answer site my task is to make sure the quality of the comments and answers are not abusive and some of yours have been.

I've tried to channel you to where your knowledge would be better served! Please create a guide on the issue!


Show 1 more comment

Add a comment

2 Answers

install mac os and some sensor reading app like istat menus. if thats palmrest temp sensor, replace trackpad / cable. idea is that one malfunctioning temp/current sensor triggers PROCHOT condition, which is minimum CPU frequency.

Was this answer helpful?

Score 0


@inwerp - Apple calls this CPU Safe Mode at the SMC & OS level. But it’s more than one sensor that can trigger it.

PROCHOT is the Intel 12th Generation CPU pin assignment to throttle the CPU. Older CPU’s used a different pin assignment.

And yes, without access to any diagnostics one can’t isolate what sensor is tripping which could be power besides temp.


@danj istat menus shows all possible sensors. unfortunately it is not documented which are not populated on which devices, but if i recall macbook air has almost all of them. also MRI image is not that hard to find online.

as mentioned, yes, one malfunctioning temp or current sensor will cause that behaviour, as well as bad battery.


@danj as for PROCHOT, this is an intel signal name which is used on all pc laptops as well as intel macs. on 820-00165 broadwell board that would be CPU_PROCHOT_L. i do not remember exactly but this signal is here since decades.


@inwerp - The point I was pointed to is this is the result of the condition not the source and the report of the fault. I wasn’t isolating the battery internal sensors out.

I find TG Pro is a better app to see what’s going on.


@danj im not sure if i understand what do you mean.

if one of sensors is not reading, smc triggers smc_prochot_l signal and sets fan to 100%. it can also be overridden with opencore bootloader. the easiest way to figure which sensor has failed if you do not have MRI or it freezes - use sensor software like iStat menus.


Show 9 more comments

Add a comment

you need to find out which process is hugging your cpu.

Was this answer helpful?

Score 0
Add a comment

Add your answer

sumit will be eternally grateful.
View Statistics:

Past 24 Hours: 0

Past 7 Days: 3

Past 30 Days: 24

All Time: 178