virtualbox.org

There is a major bug in VirtualBox 4.2.6. It's preventing me from selecting more than 1 CPU for the guest OS. The Acceleration tab is grayed out and I can't move the slider. My computer has an Intel Core i5 3570K processor. This is a quad core processor that supports Intel's VT-x virtualization. My motherboard is a Gigabyte GA-H77-D3SH with firmware version F8C. Unlike previous firmware versions this is a 100% UEFI compliant firmware from AMI and fully supports everything UEFI has to offer including Windows 8 secure boot (which is enabled). I have virtualization enabled in the motherboard's firmware. I'm trying to install Ubuntu Linux 12.10 so I can compile my own AOSP Android OS for my Nexus 4 phone. My host operating system is 64-bit Windows 8. It was installed in EFI mode, not legacy BIOS mode. Why can't VirtualBox see that VT-x is enabled on my computer? Microsoft's Hyper-V virtualization software can see this. The only reason I'm not using Hyper-V is because there are no guest drivers for Linux. How do I get VirtualBox to let me select more than 1 CPU?

There's a major bug up something, but it isn't VirtualBox.

Enable IO APIC in the VM recipe.
Disable Hyper-V.

OK, I'm new to Virtual Box and this forum, but I have the same problem enabling the 2nd CPU. I've enabled APIC, but need help with disabling Hyper-V. I installed Hyper-V before finding out that my E5200 CPU doesn't support SLAT (Secondary Level Address Translation). I haven't been able to locate where to disable Hyper-V. I don't see it in the Settings for Virtual Box and I don't see it in the Windows 8 Programs and Features applet of Windows 8. Doing a search for Hyper-V in Virtual Box's help gave no results, and searching for uninstall or disable in Hyper-V returned no results either. Could some kind soul please tell me what I need to do to disable this Hyper-V beast? TIA

I have to say that after my experience with Hyper-V, VirtualBox was a snap to install and get working AND it supports USB which Hyper-V doesn't. How MS can claim it's a replacement for XP Mode mystifies me, but then so does Windows 8! VirtualBox just downloads, installs, installs Windows XP guest and simply works without all the hassle you have with Hyper-V. It does peg the meter at 100% CPU a good bit of the time right now, but once I get that 2nd CPU enabled, I doubt if that'll be a problem. I'm aware that the E5200 (2.5 GHz, dual processor) isn't the swiftest, but it's what I have on my test machine, and I believe I can get another year or two of use with it before I have to upgrade to something like an I5 and new mobo.

TIA

Update - I went to the "Turn Windows Features on and off" section of Programs and Features and voila, I was able to uncheck the boxes for Hyper-V there. That removed Hyper-V from the Start menu. Then I rebooted and tried VirtualBox again, but it still won't let me set up the 2nd CPU, i.e. I can't drag that slider in the Settings -> System -> Processor to enable the 2nd CPU. I'm probably missing something simple, but this newbie to VirtualBox can't figure out what I'm missing. I have a lot of PC experience (since 1989), but I'm up against this newbie stumbling block. Could some kind soul tell me what I'm missing?

TIA

Can you try setting up 2 CPU using vboxmanage from a command prompt in the Virtualbox directory with the following command : Then try starting the VM and see what happens. If it doesn't work, attach as a zip file the Guest log file aswell as the showvminfo of vboxmanage - more details here

Thanks for the reply. I tried issuing the Vboxmanage from the command prompt in the host (Windows 8 ) and the guest (Windows XP SP3), but neither recognized it. Again I'm probably stumbling around missing the obvious in a newbie fog, but it's not at all apparent to me where and how to issue this command. I can't find any other place to try to enter this command. I clicked on your link and saw a lot of detail about how to issue commands once you get into this thing, but I need help in figuring out how to get into it. Sorry if I'm missing the obvious.

TIA

Not going to work. The processor does not support hardware virtualization needed for 64 bit guests & also needed for SMP on 32 bit guests.
http://ark.intel.com/products/37212/Int ... 00-MHz-FSB

Well I guess that's the answer. Thank you. It's not the answer I wanted, but at least now I know why I can't enable the other core. SMP I take it means Symmetric MultiProcessing. I guess my old E5200 chip is showing its age. I take it that if I installed VirtualBox on something with an I3, I5, or I7 processor, that would allow for multiple CPU support, right?

Yes it would, but be warned that changing an already installed Windows OS to SMP you must enable IO/APIC and this will require that you also update the Windows guest to multiprocessor which most of the time fails. There is a script/program that you can find in another topic here called HALu that helps.

Usually multiple CPUs aren't what you need for speed in a Virtual environment anyway, but you do need hardware virtualization and page tables help a lot as well for best performance.

Makes sense. Thanks again perryg. When you have to use software to simulate a hardware feature, it does eat up CPU cycles. Whenever you change mobos (which I'd need to do), you have to reinstall Windows too, so it would involve a lot of work to update a current computer, especially my test machine because I have 6 versions of Windows on it, not counting VirtualBox. At least I've got enough hardware to get it installed and working with an XP guest and get a bit of an education in the process. Now I know just enough about Hyper-V and VirtualBox to be dangerous!

You probably need to run msconfig to make Windows use all the cores...

Start - Run - type msconfig - Enter

Startup Tab the Advanced Options and you should get to a Box like this :
For some reason, Windows always defaults to 1 core... Va à savoir why.

Interesting, but it really has nothing to do with this topic.

[quote="Perryg"]Not going to work. The processor does not support hardware virtualization needed for 64 bit guests & also needed for SMP on 32 bit guests.
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I don't believe that your response is accurate (particularly the reference to the processor - E5200).

I've encountered the very same issue. My processor is a Xeon Quad-Core. I've created and installed 64bit MS OSes using Hyper-V (Win2K3/Win2K8 and Win2K12) on this machine without any problems.

On my other physical machine (using a Duo-Core Celeron) I've been able to install Win2k3 with 2 CPUs using VirtualBox.

It's just on the box with the Xeon processor that I'm having problems assinging more than 1 CPU within a VirtualBox VM. On this server I'm running WinK8 ENT 64bit

wpgwpg wrote:Well I guess that's the answer. Thank you. It's not the answer I wanted, but at least now I know why I can't enable the other core. SMP I take it means Symmetric MultiProcessing. I guess my old E5200 chip is showing its age. I take it that if I installed VirtualBox on something with an I3, I5, or I7 processor, that would allow for multiple CPU support, right?

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Please see my post below ... I'm having the exact problem with a system fitted with a Xeon Quad-Core processor.

Marcus,

Did you look in your bios, and do you see anything about hardware virtualization?