Why Won't WindowsXP Use (New) 2nd Processor?

[mikesheffler]

This may be a Windows XP-specific question, but I'll ask anyway because I can imagine others having the same issue.

I recently upgraded from VirtualBox 2.2.something to VirtualBox 3.0.0. I have a Core 2 Duo so I thought I'd give the new SMP support a whirl. I powered down my Windows guest, bumped the number of processors to "2" in the settings for that guest, and then booted it again. Now, in the Windows Device Manager, I can see two processors, but Task Manager (for instance) only sees one processor. Am I screwed, and I have to reinstall Windows to expect it to see two CPUs? Am I doing this wrong in general? I would appreciate any insight.

Thanks,

Mike Sheffler

[TerryE]

Mike there are lots of other similar threads. Please don't open yet another copy of this Q. Use one of the others as we ask in the Forum Posting Guide. So I am locking this one. If you check these the two main issues are the need for VT-x / AND-V support on the host and using the correct NT kernel in the guest.

[Sasquatch]

E.g. this topic has similar issues and solved it: http://forums.virtualbox.org/viewtopic.php?f=6&t=19402