I used to be able to run
3 VMs on Vmware Fusion at the same time on Catalina. After I upgraded my
MacBook Pro to Big Sur, even 1 vm could cause slowness. If I run the vm along
with Teams or Zoom meeting, it simply stopped responding. I couldn’t even move
the mouse sometimes.
My MacBook is Pro 2019,
32G memory, 2 video cards. CPU: 2.3GHz, 8-Core Intel Core i9. This
configuration is not that bad.
I googled and found many
users have the same problem. And there were many solutions. However, I’ve tried
all of them, including but not limited:
1.
Disable "Enable
hypervisor applications in this virtual machine"
2.
On the guest windows, on
settings > Windows Security > device security > turn off “Memory
integrity”
3.
Modify the .vmx file (https://communities.vmware.com/t5/VMware-Fusion-Discussions/VMware-Fusion-12-1-0-Big-Sur-Host-Windows-10-Guest-Running-Slow/m-p/2814913/highlight/false#M170980)
4.
Set windows.vbs.enabled
= "FALSE"
5.
Use Parallels but it
seems to have the same problem.
After many attempts, I
am thinking of moving back to Catalina, however, it means a lot of work because
I didn’t have the backup in Time-Machine.
It would be better if
the issue could be solved in Big Sur so I don’t have to rollback.
I started my investigation.
So far in my MacBook Pro, there were 4 applications that could cause the
slowness: VMware Fusion, (Parallels), Teams, Zoom. I noticed whenever the
slowness happened, there was a process call “kernel-task” that has more than
1000%CPU usage and the fan was running like crazy.
I googled what “kernel-task”
is really doing, on Apple support site
(https://support.apple.com/en-ca/HT207359), it mentioned:
Activity Monitor might
show that a system process named kernel_task is using a large percentage of
your CPU, and during this time you might notice more fan activity.
One of the functions of
kernel_task is to help manage CPU temperature by making the CPU less available
to processes that are using it intensely. In other words, kernel_task responds
to conditions that cause your CPU to become too hot, even if your Mac doesn't
feel hot to you. It does not itself cause those conditions. When the CPU
temperature decreases, kernel_task automatically reduces its activity.
So, I think, if I cool
down the laptop, maybe this process won’t use that much CPU resources.
I bought a laptop
cooling pad, it helped, now I can run 1 vm without any slowness. However, I
still couldn’t run more than 1 vm at the same time.
I need a stronger
cooler, so I took a First Aid Ice pack from the refrigerator and put it under
the laptop. Now, I can run 3 vms at the same time again.
I think maybe Apple
changed the way of how the process “kernel_task” be triggered on Big Sur to
better protect the CPU. but it causes the whole system to be slow.