Charging your MacBook Pro 2017/MacBook Pro 2019 with left-side ports overheats the CPU


Is Your 15-inch MacBook Pro 2017 or the 16-inch MacBook Pro 2019 Turning Hot or Showing A High CPU Use During Charging?

Many MacBook Pro owners have found their MacBook Pro overheating and CPU use increasing when charging using the left side ports.

If you have a MacBook Pro at home, you did have never paid attention to the fact that you randomly use the right side or left side charging ports. It becomes a matter of habit to charge the MacBook Pro or any electronic gadget from the side that we are comfortable with. However, if you indeed own a MacBook Pro, you should now make it a habit to charge it from right-side port only. Why? Read on!

It seems charging from the left side port causes the MacBook Pro to overheat due to an Apple service called Kernel Task. The issue was first noticed by a user who made a post on StackExchange. He reported seeing unusual activity in Mac’s Activity Monitor showing high CPU usage for a process called kernel_task. When the Kernel Task is overused, it causes the MacBook Pro to overheat and also reduces overall system performance. It also makes the small wee fans of MacBook Pro run ferociously to bring down the temperature of the CPU.

What is Kernel Task in MacBook Pro?

The job of the kernel_task is to manage your MacBook’s CPU temperature by deliberately throttling the CPU and making it unavailable for Apps that hog the memory. It is like a sluice valve that controls what App gets what percentage of CPU based on the demand. When a particular App demands high CPU use, the Kernel Task throttles it bringing some balance to the CPU usage. The problem with MacBook Pro is that that if you use the left port for charging, the kernel_task kicks in and starts throttling the CPU Usage without any reason. This causes the CPU percentage to rise and also overheat.

CPU usage and temperature graphs

This issue is particularly felt in 15-inch MacBook Pro 2017 and the 16-inch MacBook Pro 2019. Other MacBooks may be facing a similar issue but have not been reported yet.

Fix for this Macbook Pro heating issue?

Apple has not acknowledged this issue hence a fix come only in the next macOS Catalina update. The users at StackExchange have come up with their own solutions for your MacBook Pro 2017 and MacBook Pro 2019 heating issues. Here they are.

  • Always charge your MacBook Pro 2017 and MacBook Pro 2019 from the right side. Avoid using the right-side port for functions other than charging.
  • When you are charging from the right-side port, make it a habit to unplug any accessory like a USB or phone charging cable from the left side. Use the accessory after the charging has been done.
  • Force fans to the max before plugging in. You can do this from the iStatMenus¬† -> Fans menu. Remember, this is a temporary solution.
  • Move to a cooler room with airconditioning.

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