High CPU usage caused by system interrupts on Windows over Boot Camp

Question

vernarancs Author

Level 1

8 points

High CPU usage caused by system interrupts on Windows over Boot Camp

Hi,

I have an issue with a clean Windows 10 installation running on my MacBook Pro.

In Windows Task Manager I see a constant 7-8% "System interrupts" usage:

In Resource Monitor I see that "CPU 0" is under 100% load:

If I put the machine to sleep and wake it, the CPU usage goes down to 0%:

If I restart the machine, "CPU 0" goes back to 100% load.

Hardware:

MacBook Pro (Retina, 15-inch, Mid 2014)

Model: A1398 (EMC 2876)

ID: MacBookPro11,2

CPU: 2.2 GHz Core i7 (I7-4770HQ) (4 cores, 8 logical processors)

RAM: 16 GB

Video Card: Intel Iris Pro 5200

Storage: 256 GB SSD

The hardware of my MacBook has not been altered, the case has never been opened.

Software:

BIOS Version/Date: 159.0.0.0.0, 2020-02-05

macOS version: 10.15.4 (19E287)

Windows version: Windows 10 Pro 1909 (Build 18363, 64 bit, English)

Steps to reproduce the issue:

1. Delete Windows 10 from the machine with Boot Camp

2. Install Windows 10 Pro version 1909 (Build 18363, 64 bit, English) with Boot Camp

3. Install the latest Boot Camp Support Software

4. Install all Windows Updates

5. Observe high CPU load

What I tried so far but did not work:

1. Unplugging all devices from the laptop (external keyboard, external mouse, flash drive, etc.)

2. Installing the latest Intel Graphics Driver (version 15.40.45.5126) from https://downloadcenter.intel.com/product/81493/Intel-Iris-Pro-Graphics-5200

What I tried so far and works:

1. Putting the computer to sleep and waking it

2. Uninstalling the Intel Graphics Driver

When only the Microsoft Basic Display Adapter is installed, all CPUs are under 0% load:

After the Intel Graphics Driver gets installed, "CPU 0" goes to 100% load:

I tried several Intel Drivers:

1. 10.18.10.3345 (Oct 31, 2013) (this one gets installed with Windows)

2. 10.18.15.4240 (Jun 16, 2015) (this one gets installed with the Boot Camp Support Software)

3. 20.19.15.4531 (Sep 29, 2016) (this one gets installed with Windows Update)

4. 20.19.15.5126 (Jan 21, 2020) (this one is the latest on Intel's website)

Can someone please advise how to get this fixed?

Thank you!

MacBook Pro 15", macOS 10.15

Posted on Apr 24, 2020 12:34 PM

Reply

Answer 1

vernarancs Author

Level 1

8 points

May 9, 2020 8:48 AM in response to Loner T

Apparently high system interrupt CPU usage under Windows is a known issue since 2014: https://discussions.apple.com/thread/6598184 - the thread has more than 61,000 views.

People started experiencing this behavior after they installed Yosemite, likely the cause is a bug in the EFI update that came with it.

Reply

Answer 2

Loner T

Level 9

59,536 points

Apr 25, 2020 7:05 AM in response to vernarancs

Are there any Apple Services running? If yes, temporarily stop them and check. Do not reboot.

Reply

Answer 3

vernarancs Author

Level 1

8 points

Apr 30, 2020 2:30 PM in response to Loner T

I mean the laptop is running hotter when idle when CPU0 is 100% utilized. I can physically feel it and measure it as well.

If I disable Intel Graphics in Device Manager:

Then after a restart Intel Graphics stays disabled, CPU0 is 0% utilized and the average CPU temperature is 51 C:

If I enable Intel Graphics, CPU0 and CPU3 GET heavily utilized and the temperature increases as well:

It averages around 65 C after some time:

If I then put the computer to sleep and wake it immediately, CPU0 and CPU3 usage drops to 0% and the temperature starts decreasing as well:

I really would love to not have to put the machine to sleep after every restart...

Reply

Answer 4

Loner T

Level 9

59,536 points

May 9, 2020 9:31 AM in response to vernarancs

vernarancs wrote:

People started experiencing this behavior after they installed Yosemite, likely the cause is a bug in the EFI update that came with it.

Quite a few of the updates at EFI layer are related to security. You may want to look at Apple security updates - Apple Support.

Let me check on my 2018 rMBP.

Reply

Answer 5

Loner T

Level 9

59,536 points

Apr 24, 2020 6:32 PM in response to vernarancs

What is the behavior when you install the BC driver - 10.18.15.4240 (Jun 16, 2015) (this one gets installed with the Boot Camp Support Software) - without running any Windows Updates?

Reply

Answer 6

Loner T

Level 9

59,536 points

Apr 27, 2020 8:42 AM in response to vernarancs

Are you able to boot into Windows Safe Mode and check Task Manager for CPU? Also, you should have a multi-core CPU.

Reply

Answer 7

Loner T

Level 9

59,536 points

Apr 27, 2020 3:08 PM in response to vernarancs

Is CPU0 still at 100% when you run Selective Startup? In most cases, CPU0 is the default for most interrupts.

Reply

Answer 8

Loner T

Level 9

59,536 points

Apr 29, 2020 8:35 AM in response to vernarancs

Windows runs hotter on Macs, than normal PC. Without the Intel GPU drivers, you will lose quite a bit of functionality.

On a 2018 rMBP, the fans come on occasionally, while macOS hardly ever starts the fans. This is using normal activity, not any extensive GPU/CPU workload.

Reply

Answer 9

Loner T

Level 9

59,536 points

Apr 30, 2020 5:13 PM in response to vernarancs

After you wake up the Mac from Sleep and start using the Mac, CPU0/CPU3 should start being utilized, resulting in a higher temperature.

Also, if your 2014 Mac has never been opened, fans will accumulate dust. It should be cleaned, gently, after removing the back cover, using pressurized air.

Reply

Answer 10

vernarancs Author

Level 1

8 points

May 1, 2020 8:29 AM in response to Loner T

The machine was idle the whole time I took the screenshots, I was not running any programs. The fan did not start at all.

"After you wake up the Mac from Sleep and start using the Mac, CPU0/CPU3 should start being utilized, resulting in a higher temperature." - and yet, the opposite happens. After I wake up the laptop, CPU0/CPU3 is not put under load by system interrupts any more and the temperature decreases.

Reply