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ahmedouvix

macrumors member
Original poster
Dec 20, 2013
88
12
Hi. the last two weeks i am experiencing a horrible throttling on my macbook.

The cpu down-clock itself to 0.8GHz, Temps are staying at 60C and fans are running at maximum speed.

It always happens when i connect my tiny 1080p external monitor. also kernel_task eats over 1000% of my CPU. I Guess that's apple's way to tell me the cpu is being throttled down. to make the cpu not usable and decrease the heat. which doesn't happen at all. temps don't go lower than 60C

when it happens, my macbook is literally so slow that i can't open a single chrome tab.

I have to turn it off and wait for 10-20 mins to cool it down so i open it again to have normal CPU clocks for a couple minutes before it happens again.

I am so desperate to find any solution. i have a graduation project that needs to be completed the next few days. my project requires primavera p6 which i use on parallels windows 10.

the laptop throttles 2 seconds after opening parallels. i can't do anything on it and i am literally have no idea what do.

Please help a desperate student whose life about to be ruined... i spent the last 2 weeks trying to fix this issue with no hope. i really need to complete my project the next 2 days and i can't even boot to windows.

i tried reinstalling 10.13.4, 10.13.5 with no restoring back up. it also happens on boot camp w10 1803.
reset SMC, nvram not working. running diagnostics (cmd+d) tells me there is no problem. running a fan directly to the keyboard doesn't help too. under-volting on windows or macOS is not supported, thanks apple.

Please note it always happens while using an external monitor...

there is no apple stores where i live and authorized reseller needs a week to just check what's wrong with it.

thank you
 

duervo

macrumors 68020
Feb 5, 2011
2,470
1,239
Take the bottom off and check for dust, and use a can of compressed air to clean out if necessary. This (high kernel_task CPU usage) can happen if there’s enough dust inside to impact the cooling.

High kernel_task CPU is actually Apple’s way of controlling a process’s access to CPU if the cooling system cannot keep the CPU cooled to a normal level. I.e.: “Crap, fans are on full, and my CPU is still too hot. Hey Parallels, step back and give my CPU some breathing room.” It’s debatable wether or not this is the best approach, as kernel_task itself can end up consuming CPU just by having to control CPU access to several busy processes. Nevertheless, it’s what Apple chooses to do, along with things like throttling the CPU. I can’t think of a better way ... not that I’ve ever given it much thought though.
 
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ahmedouvix

macrumors member
Original poster
Dec 20, 2013
88
12
Take the bottom off and check for dust, and use a can of compressed air to clean out if necessary. This (high kernel_task CPU usage) can happen if there’s enough dust inside to impact the cooling.

High kernel_task CPU is actually Apple’s way of controlling a process’s access to CPU if the cooling system cannot keep the CPU cooled to a normal level. I.e.: “Crap, fans are on full, and my CPU is still too hot. Hey Parallels, step back and give my CPU some breathing room.” It’s debatable wether or not this is the best approach, as kernel_task itself can end up consuming CPU just by having to control CPU access to several busy processes. Nevertheless, it’s what Apple chooses to do, along with things like throttling the CPU. I can’t think of a better way ... not that I’ve ever given it much thought though.

i bought a pentalobe screwdriver from aliexpress to clean the macbook and to do a thermal repaste. but that was a month ago and i guess it got lost in shipping. i am definitely going to clean inside the macbook after finding the screw driver. sadly i can't find anywhere in my country.

the weird thing is that it never happens on clamshell mode or when i don't connect the external monitor. not sure why

also about kernel_task. it sucks. it happens at 60C which isn't a very high temperature. i had an HP laptop before. it throttles to 1.1 GHz after reaching 90C and still fully usable. even for gaming.

i don't think it's thermal throttle on the macbook and it's other kind of throttle, power throttle maybe.
 

duervo

macrumors 68020
Feb 5, 2011
2,470
1,239
i bought a pentalobe screwdriver from aliexpress to clean the macbook and to do a thermal repaste. but that was a month ago and i guess it got lost in shipping. i am definitely going to clean inside the macbook after finding the screw driver. sadly i can't find anywhere in my country.

the weird thing is that it never happens on clamshell mode or when i don't connect the external monitor. not sure why

also about kernel_task. it sucks. it happens at 60C which isn't a very high temperature. i had an HP laptop before. it throttles to 1.1 GHz after reaching 90C and still fully usable. even for gaming.

i don't think it's thermal throttle on the macbook and it's other kind of throttle, power throttle maybe.

What’s the temperature of the GPU? System fans would turn on if temp for that is high enough, which it might be higher when both external display and internal display is on (not in clamshell mode.)

Anyway ... yeah, check for dust. That’s what I’d do. Can’t do more than that, given what you’ve already done. If cleaning dust out doesn’t fix it, you’ll have to look to Apple for help ... after you get your work done. If there’s any wat that you can just use the internal display to get your work done in the meantime, then that’s what I’d do, as that’s more important right now.
 
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AppleHaterLover

macrumors 68020
Jun 15, 2018
2,048
2,051
I had a similar issue, processor would stay at 3.1 GHz Turbo Boost flat (it is 2.3 GHz originally), hot to the touch, battery would last 30 seconds.

Turns out it was cryptomining malware hitching a ride on my CPU - "mshelper". Unistalled it and it all came back to normal. Suggest you check that.
 

ahmedouvix

macrumors member
Original poster
Dec 20, 2013
88
12
What’s the temperature of the GPU? System fans would turn on if temp for that is high enough, which it might be higher when both external display and internal display is on (not in clamshell mode.)

Anyway ... yeah, check for dust. That’s what I’d do. Can’t do more than that, given what you’ve already done. If cleaning dust out doesn’t fix it, you’ll have to look to Apple for help ... after you get your work done. If there’s any wat that you can just use the internal display to get your work done in the meantime, then that’s what I’d do, as that’s more important right now.

the temperature of GPU is 53 and CPU is 60C. kernel_task is running and fans at maximum speed so it don't get high than that

thanks for helping

I had a similar issue, processor would stay at 3.1 GHz Turbo Boost flat (it is 2.3 GHz originally), hot to the touch, battery would last 30 seconds.

Turns out it was cryptomining malware hitching a ride on my CPU - "mshelper". Unistalled it and it all came back to normal. Suggest you check that.

couldn't find anything related.. did a scan with malwarebyte and found a virus though

https://imgur.com/a/wI6xruY
 
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maflynn

macrumors Haswell
May 3, 2009
73,682
43,709
the temperature of GPU is 53 and CPU is 60C. kernel_task is running and fans at maximum speed so it don't get high than that
I just incurred this very issue on my 2018 MBP. It wasn't hot (60c) and I wasn't doing anything other then safari. Rebooting fixed it for me, but I'm going to keep an eye on things.

While I understand this is an apple mechanism to protect the innards from cooking themselves, my temps and processes were not an issue.
 

Fishrrman

macrumors Penryn
Feb 20, 2009
28,613
12,735
The OP wrote:
"It always happens when i connect my tiny 1080p external monitor."

...and also wrote:
"I am so desperate to find any solution. i have a graduation project that needs to be completed the next few days."

Old story:
Patient to doctor:
"It hurts when I do this"
Doctor to patient:
"Then... don't do that".

Therein lies your solution to get your graduation project done.

Time to start shopping for another display.
 
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