MacBook Pro 15" 2018 Full Fans and Kernel_Task at 9800%

[remigi]

I am using a 15" Macbook Pro (2018) but since installing 10.15.4 I am having problems that are unbearable. At this point in time I am not sure if it is the second monitor I connected or the installation of 10.15.4 as they both happened with in a few days of each other but my Macbook has basically become unusable.

I have 2 monitors:
- 1x Dell U2518D - Connected via USB-C > mDP (Adapter) mDP>DP cable.
- 1x Dell U2520D - Connected via USB-C Right side
I run my MacBook with the lid closed almost all day using an external Apple Keyboard and Bluetooth mouse. When first switching on the Mac, the fans will be quiet but within about 15 minutes they will run full speed and stay like that all day. Then randomly throughout the day I will get a Kernel_Task kick in, the temperatures haven't changed or spiked but for some reason the Kernel_Task kicks in and the Mac grinds to a total halt. The only way to stop this is to unplug both monitors and stop all work. Most of the time it recovers but sometimes you need to reboot.

I originally thought this was a OS installation issue, so yesterday I formatted with a clean install of 10.15.4, within minutes of booting up the fans kicked in and as soon as I started sync'ing my Google Drive, the Kernel_Task came back and the Mac was useless again.

The Kernel_Task issue is most noticeable anytime there is any video involved - i.e. Google Hangouts Meeting, WebEx, Youtube... anything like that you can almost guarantee this happens. To the point where my Bluetooth mouse and headphones disconnect and audio drops because the Kernel_Task is so high.

When there is a unexplained Kernel_Task - CPU 60 degrees

Right now - CPU 61 Degrees - No Kernel_Task

During Today's Kernel_Task Spike - Initiated a Download of a JPG from a Logo Designing Website, suddenly Kernel_Task spike

 

[remigi]

So, an update from this morning.

Monitoring the temperatures during standard chrome usage - 3 browser windows, one open on each monitor plus one minimized. I noticed that the fans have a direct correlation to the palm rest sensors

Palm Rest 1 - 34 Degrees Celcius = 3800 > 4800 RPM

Then

Palm Rest 1 - 36 Degrees Celcius = 4800 > 5800 RPM

Now since the Palm Rest never drops below that again in Clamshell mode, the fans stay at a constant full speed of 5800RPM

Video: https://www.dropbox.com/s/k10q9djbe5p9053/Temps.mp4?dl=0

 

[JPRUSER]

Hey there, I don't know if you're still having the same issue, but I will post what I did for future visitors.

I was having the same issue with a MacBook Pro 2018 15" connected to an external 27" samsung monitor. Kernel task was using sometimes 1000%, which is basically 10 threads out of 12, which is a nightmare, because the macbook becomes useless, so I read that there is something called freeSync in the samsung monitor that regulates the refresh rate between the AMD radeon and the screen itself. I enabled the freeSync option in the monitor and so far it is working fine without any issues even when executing codes that use up to 11 threads, so if you have freeSync in your monitor you may want to give that a try.

I hope my comment helps.

cheers

 

[harrydag]

Hi, late reply to this but anyone who found this thread from googling the problem I found a solution that works for me. I was having the same problem, whenever using google meet, any type of game, or even youtube my kernel_task would jump a ton and slow down my whole computer. I ran a CPU benchmark (Geekbench 5) and got a single-core score of 237 and a multi-core score of 1357. All I did was remove the back of my mac and spray compressed air through the fans, radiators, and vent (as well as around the rest of the computer to clean it up) and ran the benchmark again and got scores of 1055 for single-core and 6692 for multi-core. I haven't truly stress tested it yet but everything seems to be running better. If you don't feel confident doing it yourself I've heard the apple store will do it for you if you specifically ask for it, if not, they may tell you they need to replace the motherboard ($1000+). Removing the back is fairly simple, just needs a bit of force after the screws are out but there are plenty of walkthroughs online!

Hope this helps!

Specs:
2019 16in Macbook Pro,
2.3 GHz 8-Core Intel Core i9
32 GB DDR4 RAM
AMD Radeon Pro 5500M 8GB
macOS Big Sur 11.5.1