2 equal CPU driver: Can't deinstall one

[Plagrö]

Hello,

I have a VM of Windows 7.
As CPU in the VM settings I chose 2 CPU's, because my old computer from where this Windows 7 image was produced was a dual core.

It worked fine. All drivers were replaced.

So in the meantime I decided to change the number of CPU's from 2 to 8. I thought: "Why leave 6 CPU's unused. Maybe when I choose 2 CPU's, then these 2 CPU's are overused. It might be better for the lifetime of my hardware if I select all CPU's for the virtual machine. This way, all CPUs are stressed equal." (No idea.)

So I changed the CPU setting in my VM to 8 CPU's. But again. Booting fells still a little bit slower as before. (Edit)

This worked great. A new driver was installed.

But I did not find any differences. The different CPU's are used quite similar as before. And it feels like booting is slower now as before. So I changed back the CPU setting to 2 CPU's. Edit: But booting feels still a little bit slower as before.

In the meantime I had a look into the device manager. There I found, that 2 equal drivers are installed.

I tried to delete one of them:
I deleted it, started the VM again. Then during booting it automatically installed a driver again, and I have again 2 equal drivers installed. I also tried to delete the other of the two. But the same thing happens.

Question: How can I get rid of the second driver? Thank you.

[scottgus1]

So I changed the CPU setting in my VM to 8 CPU's. But again. Booting fells still a little bit slower as before.
.... And it feels like booting is slower now as before.

This is expected. The more processors in a guest, the more scheduling overhead to assign tasks and threads to the processors, which takes up some of the processor time. And if there isn't enough tasks & threads to go around, the tasks & threads that are there get a little slower.

What exactly do you mean by "the second driver"? Maybe a screenshot, cropped & resized appropriately & posted using the forum's Upload Attachment tab.

[Plagrö]

Thank you.

Here is the requested printscreen:

CPU Treiber VM.PNG (39.43 KiB) Viewed 1105 times

[mpack]

As I expected, the i5-4570 is in fact a 4 core CPU, not 8 core. So a fair division of resources with the host implies a maximum of 2 cores to a single running VM. If the VM has already been reverted to two vCPU (which is what the screenshot also says) then I suggest: stop messing with it.

FAQ: Cores vs Threads.

[Plagrö]

Thanks.
I misinterpreted the two entries in the device manager. I thought there were two drivers installed, one old and one new. But it seems to require an entry for each core.

Thank you also for the link.

[scottgus1]

require an entry for each core

Yes, that's common to all multi-core Windows PCs. the quad-core Atom tablet I'm typing on has four 'drivers' showing.