VirtualBox and 64bit systems

I was trying to install trial 2008 server (64 bit) on VirtualBox solution for virtualization.
I’ve enabled in BIOS VT-x and … was sure that it will start. But some problem occured. Installer of Windows 2008 has returned error:
0xC0000225
and wrote something about hardware or configuration modyfication.

There are many options in VirtualBox that pottentialy can help – but which?
I’ve tried some of them and it seems that found the cause:
It was an option related to vritaul machine under:

• System tab
• Motherboard
• Extended feature

Enable IO APIC

After enabling this option I’ve started installer of Windows 2008 and it works.

There is also some explanation about this parameter:

Enable I/O APIC

Advanced Programmable Interrupt Controllers (APICs) are a newer x86 hardware feature that have replaced old-style Programmable Interrupt Controllers (PICs) in recent years. With an I/O APIC, operating systems can use more than 16 interrupt requests (IRQs) and therefore avoid IRQ sharing for improved reliability.

Note

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.

However, software support for I/O APICs has been unreliable with some operating systems other than Windows. Also, the use of an I/O APIC slightly increases the overhead of virtualization and therefore slows down the guest OS a little.