[Solved] Only one CPU on Win 10 host

[AlainJM]

Yes, I know, I can hear the sighs from here... I have done a bit of research and tried a bunch of things already. But I still cannot make it work. I'm sorry.

I installed VirtualBox 6.1.6 on a Win 10 1909 PC (fresh install for VBox), it is an X299 with an I9 7940X. And I have an Ubuntu 18.04 guest (desktop) running within it.

Intel Virtualization is enabled in the BIOS, I don’t have any other virtualization software. I checked the list at f=1&t=62339 but found nothing there that matches. I just ran

Code: Select all

bcdedit /set hypervisorlaunchtype off

and Windows told me that the operation was successful, then shut down, powered down, waited, booted. No change.

Or would I have to rebuild the guest? Or to reinstall VirtualBox? But I never had to change the BIOS or deactivate a Windows feature to comply with the usual solutions. It was clean from scratch, as far I can tell.

The only thing that is not totally usual on this setup is the presence of a Linux partition (also Ubuntu 18.04), so that I must switch to Windows in the Ubuntu boot screen when the computer starts. And it has McAfee Total Access, but it never complained of anything. Shall I try and get rid of those?

[mpack]

You went directly into defensive mode without actually describing your problem. As you can see from the following log extract:-

00:00:02.547788 NumCPUs <integer> = 0x0000000000000001 (1)
...
00:00:03.475361 CPUM: Physical host cores: 14

VirtualBox has no trouble seeing that the host CPU has 14 cores, but you only allocated 1 to the VM. You gave no indication that you attempted to change this, instead you seem to have diverted yourself into an irrelevant consideration of Hyper-v for no obvious reason: there is no indication in the log that anything is blocking you from using VT-x.

p.s. In any case with VirtualBox 6.1.x the lack of VT-x no longer relates to the ability to choose >1 vCPUs. That's because VT-x is not optional any longer, so if it wasn't available then selecting >1 vCPU would be the least of your problems.

p.p.s. 18GB RAM for a VM seems excessive to me, when you only have 26GB available, and especially since the hdd is only 48GB (does Ubuntu still reserve 1.5*RAM as the swap partition size?). I tend towards giving a VM no more than it needs, that way I reduce stress on the host, which is where VirtualBox runs. I would suggest 8GB RAM, 2 cores. Also, I doubt your Ubuntu guest will be happy with only 16MB graphics RAM - I'd increase that to 128MB.

[AlainJM]

I can't allocate more cores to VBox, or I wouldn't know how? The settings (Machine -> System -> Processor) are stuck on 1 and greyed out. Hovering over it, a tooltip tells me:

Controls the number of virtual CPUs in the virtual machine. You need hardware virtualization support on your host system to use more than one virtual CPU.

During the installation, the software never asked me how many CPUs I wanted to allocate. I took it for granted that I would have the whole thing handy, perhaps minus what is needed for the GPUs. I noticed the problem while running an application in Ubuntu and first thought it was the "culprit." Then I digged into it and saw that the VBox doesn't allow me to use more than one CPU.

As for the RAM, I was overgenerous because it doesn't really matter here. I just wanted to avoid any bottleneck at that level. But you are right of course.

[Martin]

You need to shut down the guest completely.
Changing VM parameters while the guest is in a saved state isn't possible.

[AlainJM]

Indeed, thank you Martin!
Sorry to have behaved like this, but seeing the number of such problems, I felt the need to show that I had at least tried my best.

[mpack]

Topic marked as solved. Thanks for reporting back.