VirtualBox not maxing out CPU?

Cheetah Designs · 2 Mar 2011 at 15:17

Is there something that I may not have enabled in settings that would prevent VirtualBox from maxing out my i3 CPU?

Cheetah Designs · 2 Mar 2011 at 15:38

Ah right...that makes a little more sense.....it seems to be using around 25% of my CPU though when it's maxed out. With the 25% being spread over all cores (according to windows)

Cheetah Designs · 2 Mar 2011 at 15:46

Well I am doing compiling stuff in Ubuntu in a VirtualBox and it doesn't max out the CPU.

I have also run super-pi to check that its not just that task, but it isn't.

Cheetah Designs · 3 Mar 2011 at 12:43

Ah...I need to set the number of CPUs to 2 in the virtual box settings...

I thought that Virtualbox would spread the load automatically if I put 1 CPU.

I have the option to select up to 4 CPUs i think (probably due to hyperthreading)...should I....or do I leave it at 2?

When I select 2 CPUs it uses a maximum of 50%...and compilation takes 1 min 55 seconds....when I select 4 it goes up to about 90% sometimes and takes 2 mins 12 seconds...

....no idea why its slower...

Cheetah Designs · 3 Mar 2011 at 12:50

aln said:
25% sounds like its using 1 of your 4 threads (if your cpu has 4). Tell it to use more if you want more, but this will require a reboot of the VM afaik.

This appears to be true.....but that said....the 25% is split over all the Threads.