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On my Windows XP SP3 (32-bit) machine (Intel Pentium Dual CPU E2140 1.60GHz, 3GB RAM), I installed VirtualBox (4.0.10). I then tried to install a 64-bit OS like Windows 7 64-bit or Windows Server 2008 R2 64-bit on the VM. However I got an error.

I think the error stated that my machine is unable to run a 64-bit OS but actually VirtualBox in this case should be capable of running 64-bit OSes on a 32-bit host. Is that right?

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migrated from Jul 14 '11 at 11:16

This question came from our site for professional and enthusiast programmers.

up vote 3 down vote accepted

The following was approximately copied from here:

VirtualBox supports 64-bit guest operating systems on 32-bit host operating systems, provided that the following conditions are met:

  1. You need a 64-bit processor with hardware virtualization support.
  2. You must enable hardware virtualization for the particular VM for which you want 64-bit support; software virtualization is not supported for 64-bit VMs.
  3. If you want to use 64-bit guest support on a 32-bit host operating system, you must also select a 64-bit operating system for the particular VM. Since supporting 64 bits on 32-bits incurs additional overhead, VirtualBox only enables this support upon explicit request.

According to this, your processor cannot meet the 2nd condition because it does not support "Intel® Virtualization Technology (VT-x)".

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I can confirm that VMWare is pretty much the same thing. I run x86_64 RHEL5 on top of i386 RHEL4 all the time... but you need the CPU/BIOS support for 64-bit there too. – Aaron D. Marasco Jul 14 '11 at 1:08
I didn't even think about this before, but you can try QEMU. It supports 64-bit guests on 32-bit hosts without hardware virtualization. However, it is considerably slower than other VMs because it does actual emulation. To make things a bit faster use the KQEMU module. – mwk Jul 14 '11 at 2:17

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