Windows 10 VM CPU percentage at idle? (post your numbers)

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BAT77

Junior Member
Hi everyone! Q: What percentage of of your CPU does Windows 10 VM use at idle (viewed in Activity Monitor)? [Please also state your Mac model, OS, and whether your Windows 10 is a disk image or installed in a Boot Camp partition.]

I am running Windows 10 Education VM installed on a Boot Camp partition using Parallels 13 on a 2015 MacBook Pro 15-inch (2.5 GHz) with High Sierra. My dilemma: At idle Windows 10 shows a total of 3% CPU usage in (Windows) Task Manager but a whopping 25% under (Mac) Activity Monitor. I have allocated the recommended number of CPU cores, memory, etc. to Windows 10.

In contrast: My Windows 10 Education VM on my 2013 Mac Pro (6-core 3.5 GHz--the "trashcan" model), also installed on Boot Camp, shows only about 5% CPU utilization in Activity Monitor. (All settings are recommended--the same as on the MacBook Pro.)

Looking forward to the results. Thanks!
 
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On mine it is currently varying between 0.3 and 0.5%.
Windows fluctuates between 0% and 1%.
i7 4GHz 32GBRAM.
How much RAM do you have?. One 'drinker' would be if things were swapping.
 
Thanks for your reply, RogerH6. I have 16 GB RAM on the MacBook Pro. What is your macOS? And are you running Windows 10 off of Boot Camp or as a disk image?
 
Disk image. 10.13.6 on the Mac, and running 1803 on the Windows.
There was a spate of threads about high CPU usage (resulting in Mac's running hot), when Parallels 12 launched.
If I remember two culprits. Chrome, and one particular anti-virus.
I think he key was that certain things resulted in the Mac OS doing all the actual 'work' and if you were running something that triggered these, it gave the odd asymmetry between the reported readings.
 
Roger, thanks for your response. I'm amazed at how low your CPU usage on Activity Monitor is for your Boot Camp Windows 10 VM. I would expect low numbers running off a disk image, but I am surprised that the percentage is actually lower in Activity Monitor than in Windows. I would expect the opposite.
As far as CPU-sucking culprits go, I don't have Chrome installed and no anti-virus other than Windows Defender.
I did a remote session with Parallels tech support but the representative is still puzzled as to the culprit. He is doing some internally investigation and will get back to me.
Thanks again for your replies.
 
The Windows I'm running is only setup to use 4 CPU cores. So half the processor is unused by the virtual machine.
This gave me huge problems when registering Windows (I had set i up in BootCamp which had all 8 cores in use, then went to use this inside the Mac environment with only 4 cores, and Windows complained it wasn't registered - MS let me re-register after a phone call and it now accepts both configurations).
 
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Interesting thread, I was also wondering.
I'm using Parallels 13 on a Macbook Pro 13 2018 with an i7 4 cores.
Windows Pro x64 build 1803 in a VM.
I get 3-4% in Windows on idle, and 15-25% on the mac for the VM. No idea why.
There is no app running in the VM, as confirmed in the task manager.
 
That is interesting. So you are effectively seeing the same thing. I wonder if the behaviour is specific to having the VM using all the cores?. If you think about it this potentially could mean delays in servicing things on the host OS. My low Windows percentage may be because I have everything turned off (no animations, Cortama etc..).
 
Not using all cores here, two for Mac OS, two for the VM. I'm usjng the parallels hypervisor but not the adaptive one. Are you using it? Indisabled it because it causes issue with a specific software, but it could be part of the difference. I'm away this week-end but I'll trybwhen I'm back.
 
The poster is talking running the VM from a BootCamp setup. With this, you normally have to set the VM to use the same settings as are set for the BootCamp, otherwise Windows complains that the hardware has changed and it is not registered (that was the fun I had getting this to work...).
I'm using the adaptive hypervisor.
 
The poster is running from bootcamp but asked for numbers for bootcamp or disk image users.

I use bootcamp as a separate installation. It also kept asking me to reregister windows or office when I was trying to also run it as a VM, so I stopped doing that a long time ago.
 
RogerH6 said:
The Windows I'm running is only setup to use 4 CPU cores. So half the processor is unused by the virtual machine.
This gave me huge problems when registering Windows (I had set i up in BootCamp which had all 8 cores in use, then went to use this inside the Mac environment with only 4 cores, and Windows complained it wasn't registered - MS let me re-register after a phone call and it now accepts both configurations).
Click to expand...
Roger, from what I understand, this is typical no matter what core configuration you choose. Windows views the VM as a distinct machine (a separate installation) from Boot Camp, and you always have to call Microsoft to explain the situation.
 
EmmanuelO1 said:
Not using all cores here, two for Mac OS, two for the VM. I'm usjng the parallels hypervisor but not the adaptive one. Are you using it? Indisabled it because it causes issue with a specific software, but it could be part of the difference. I'm away this week-end but I'll trybwhen I'm back.
Click to expand...
Emmanuel, your i7 has hyper-threading so has a total of 8 (virtual) cores. When you allocate 2 to the VM, you have 6 left over for the macOS.
 
RogerH6 said:
On mine it is currently varying between 0.3 and 0.5%.
Windows fluctuates between 0% and 1%.
i7 4GHz 32GBRAM.
How much RAM do you have?. One 'drinker' would be if things were swapping.
Click to expand...
Roger, when you say Windows 10 shows between 0.3 and 0.5% CPU usage on Activity Monitor, are you saying it's using 0.5% of a single core? That seems incredibly low! Or are you referring to the "Parallels Desktop" process on Activity Monitor? (Mine also idles under 1%.) I'm differentiating between the "Parallels Desktop" process and the VM process--on my machine titled "Windows 10 (Boot Camp)."
Finally, what computer do you have? (It sounds like an iMac.)
 
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That's funny, posted a reply yesterday, and it doesn't seem to have appeared.
I have two VM's. The bootcamp one is heavily optimised to minimise it's CPU usage. Spent an age making sure it didn't waste any performance. It is quite interesting to boot the other and compare. That sits at about 3% typically. The optimised one is actually drawing less than the activity monitor itself!...
Yes, iMac 27" Retina, with a 4TB fusion drive. I think this does seem at times to reduce the CPU usage.
 
RogerH6 said:
That's funny, posted a reply yesterday, and it doesn't seem to have appeared.
I have two VM's. The bootcamp one is heavily optimised to minimise it's CPU usage. Spent an age making sure it didn't waste any performance. It is quite interesting to boot the other and compare. That sits at about 3% typically. The optimised one is actually drawing less than the activity monitor itself!...
Yes, iMac 27" Retina, with a 4TB fusion drive. I think this does seem at times to reduce the CPU usage.
Click to expand...
Care to share any tips on how to optimize the Boot Camp VM to minimize CPU usage? :)
 
BAT77 said:
Emmanuel, your i7 has hyper-threading so has a total of 8 (virtual) cores. When you allocate 2 to the VM, you have 6 left over for the macOS.
Click to expand...
Sorry I meant processors, not cores. I have four processors and allocate two (four hyper-threading cores) to the VM. That's the recommended value.
 
Wondering if this is a limitation of my non-pro version.
With an i7, should I see 8 processors in Parallels config?
I always thought that with a quad core, it was normal to see 4 processors, and recommended to allocated half (so two in my case) to the VM. If I allocate 4, I don't get better performance, rather worse.
Also with my MBP 13 mid 2012, I had two processors available, not four, which makes sense as it was a dualcore.
So I never thought the 4 processors for my quadcore i7 was a limitation of parallels. Am I correct?
 
I wonder if the difference in CPU use, depends on the version of Parallels?...
Just moved to V14, and am seeing enormous usage spikes. Walked away from the machine, and came back to find it had it's fans running. Windows10 being shown with 399.6% CPU usage. Stopped after a few minutes, but something really odd is happening to the CPU under Parallels 14. :(
 
I never upgrade parallels until the new OS is available. There is only 30 days of support and I want to be able to test the new version under the OS it's going to be used with.
14 might be optimized for Mojave and not High Sierra. Or there might be a bug in Mojave that will be corrected by the time it's released.
Which OS are you using with V14? Mojave beta or High Sierra?
By the way, I'm still on High Sierra and I've tried doubling the number of processors in Parallels from 2 to 4 (the maximum).
Was very surprised to see a jump of 50% in CPU performance. Very significant, and can be felt in real use.
Mac OS remains usable, and in any case I shutdown my VM when I'm actually working in Mac OS and need proper perf, as I have some apps that don't like the Adaptive supervisor so can't use it.
I still don't know if the number of processors in Parallels configuration are cores or threads, as suggested by a poster earlier.
If threads, it would make sense that I can allocate 4 a get good performance. If cores, in theory that could lead to worse performance.
I don't have pro, only standard (not the subscription one) so I'm not sure why this is the case, but I'll take the performance boost.
This is with my new MBP 13 2018 with a quadcore i7.
With my old MBP13 2012 (dual core), I also used two "processors" (the maximum) for best performance now that I think about it.
I also have near 400% use for the Win10 VM in the Mac, but again this doesn't cause any perf degradation that I can see in the VM.
 
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