Virtualbox Cpu Limiter

[pn123]

hi guys,

i am using virtual box 6.1.34 on my windows 10 64bit system, ryzen 5950x.
i start vm to launch an efi.file.


in my host windows i have a load of about 50% then.
now i have seen that in virtualbox you can adjust the load, but nothing changes in my host load.


cores etc i would like to leave as is, would only like to limit the vm load on the host at certain times.
is there anything else i need to adjust?

[scottgus1]

Start the VM from full normal shutdown, not save-state. Run until you see the problem happen, then shut down the VM from within the VM's OS if possible. If not possible, close the Virtualbox window for the VM with the Power Off option set.

Right-click the VM in the main Virtualbox window's VM list, choose Show Log. Save the far left tab's log, zip it, and post the zip file, using the forum's Upload Attachment tab.

[pn123]

hi scottgus,

the only error is that i can't limit the cpu usage.

i thought i could for example lower the vm to 60% so that my host is no longer at 50% load. (host 50% with 100% vm cpu settings).

[pn123]

I have now tried it on the 2nd computer and found a single difference (in bios is also all the same)

Pc1 cpu 5950x, mobo b450 gaming plus max -> cpu limiter works
working vm status: layer : vt-x/amd-v, nested active, unrestricted exe active

pc2 cpu 5950x, mobo b550 tomahawk -> cpu limiter doesnt work
working vm status: layer: nativ api, nested inactive, unrestricted exe inactive

can this be the reason? what do i have to change?

[mpack]

If you want your VM to use less CPU, give it fewer cores. 2 is usually the best number - more will often make a VM run slower. The CPU cap is not really relevant in the modern era, put it back to 100%.

But the main reason you're running slow is because Hyper-v is enabled on the host.

00:00:02.087566 HM: HMR3Init: Attempting fall back to NEM: AMD-V is not available
00:00:02.114285 NEM: info: Found optional import WinHvPlatform.dll!WHvQueryGpaRangeDirtyBitmap.
00:00:02.114335 NEM: WHvCapabilityCodeHypervisorPresent is TRUE, so this might work...

See HMR3Init: Attempting fall back to NEM (Hyper-V is active).

[pn123]

thank you very much for your help, it works now

the error was really the enabled hyper-v.
deactivated, reboot and it works

[scottgus1]

Pn123, forum vandalism is a serious violation. You went back and deleted the VM log. That is forum vandalism. Put it back, or you will be banned.