Take the 2-minute tour ×
Ask Ubuntu is a question and answer site for Ubuntu users and developers. It's 100% free, no registration required.

I set 2 CPU on virtualbox xp and boot successfully.

enter image description here

But when I use speccy to check.

It says I only have 1 cpu and only 1 core.

enter image description here

enter image description here

What happened?

How do I enable the second CPU?

Thank you~

share|improve this question
    
Did you enable VT-x in BIOS? –  Takkat Dec 20 '11 at 7:48
    
Did you enable I/O APIC for the VM before installing Windows? –  Takkat Dec 20 '11 at 8:06
    
Yes,I have enabled VT-x in BIOS. But I do not enable I/O APIC before installing windows. How to fix it? Thank you~ –  sam Dec 20 '11 at 9:16
    
may be as an old operating system(Win XP) it wouldn't support 2 CPU in hardware –  Naruto Dec 20 '11 at 12:35
    
Here is solution (use devcon utility and execute two commands) - superuser.com/a/456617 –  user60072 Jan 19 '13 at 10:54

1 Answer 1

up vote 2 down vote accepted

For Windows 64-bit guest and if you want to use more than 1 CPU in your guest we need to enable I/O APIC prior to installing Windows.

Enabling the I/O APIC is required for 64-bit guest operating systems, especially Windows Vista; it is also required if you want to use more than one virtual CPU in a virtual machine.

Reference: Virtual Box User Manual

This can be done in the System -> Motherboard setting in the VirtualBox Manager.

enter image description here

Note: These setting has to be made before installing Windows as only then Windows will be installed with the appropriate kernel.

share|improve this answer
    
I use 32-bit XP. And I also have already enabled IO APIC. What can I do next? Thank you~ –  sam Dec 20 '11 at 10:20
    
@sam: as said, you may need to reinstall XP with these settings. –  Takkat Dec 20 '11 at 10:25
    
I can't reinstall xp because some software problems. Is there any other way to get this function without reinstall? –  sam Dec 20 '11 at 13:49
    
I don't know if you can change the Windows kernel without fresh install (may well be you can't). Consider asking this on superuser.com –  Takkat Dec 20 '11 at 13:56
    
According to this blog post you can simply run the following in a command prompt within the windows guest: rundll32 syssetup,SetupInfObjectInstallAction ACPIAPIC_MP_HAL 128 %windir%\inf\hal.inf and then reboot twice as prompted. –  davitenio Dec 13 '13 at 7:43

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.