Common KVM processor

twentytwo

New Member
Jan 18, 2020
28
0
1
36
Australia
Hello,

When I checked the Task Manager in Windows 10 and viewed Performance, the selected CPU is worded "Common KVM processor" instead of name of the CPU? Intel i7 8600K. What can I do to make it read the CPU name instead of common KVM processor? Does correcting the name affect the overall VM performance?
 

sg90

Well-Known Member
Sep 21, 2018
287
42
48
32
On the VM Wizard change the CPU type to host, you can also do this by selecting the VM Hardware Tab - > Processor and then edit.

You need to stop and start the VM for this to take effect.
 

LnxBil

Famous Member
Feb 21, 2015
6,706
880
163
Saarland, Germany
Does correcting the name affect the overall VM performance?

Not easy to answer, but mostly yes. It has a lot of implications.

The whole idea about virtualization is to virtualize every computing resource, so it is natural to use also the virtualized CPU. Windows will detect that it is running on virtualized hardware anyways.
 
  • Like
Reactions: twentytwo

DurzoBlint123

New Member
Mar 16, 2022
8
0
1
42
I know this is an old post, but here is just a quick note for anyone else googling this. I wasn't paying attention when I originally built my Win11 VM, and left the default selection of Common KVM Processor. When I shut down the VM, changed the processor to "Host" and started it back up again, device manager still showed it has "Common KVM Processor". I attempted to right click on the device and select "Updates Drivers", but it stated that the drivers were already correct.
It wasn't until I rebooted a second time just to try it, that the processor in the VM's device manager showed "Intel Core i7...".
 

bzb-rs

Member
Jun 8, 2022
40
2
8
Canada
But is there any actual performance enhancement if we select the right model or use 'host' option instead of common kvm processor?
 

LnxBil

Famous Member
Feb 21, 2015
6,706
880
163
Saarland, Germany
But is there any actual performance enhancement if we select the right model or use 'host' option instead of common kvm processor?
Yes. If the general processor is not presenting a cpu flag and passing through does, you will be able to use the cpu flag inside of the guest and optimized code will be able to use it. Best example is the AES-NI instruction and I tested this years ago (not sure if it is still true). Without the passthrough, 192-bit AES CBC was done in software, after activating the cpu flag and using optimized code, the operation was done in hardware and was much faster. The downside of this is, that you will lose the ability to migrate the VM to other nodes if you use some cpu flags or cpu=host and thas is worse than being able to use have a little more speed, but if you only have one node or don't care about HA, go for it.
 
  • Like
Reactions: bzb-rs

About

The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get your own in 60 seconds.

Buy now!