Can a 64-bit OS run as a guest on a 64-bit VirtualBox host?

Solution 1:

Yes, you can run a 64-bit OS as a guest with VirtualBox on a 64-bit host.

VirtualBox will definitely allow usage of multiple cores on guest machines, but it depends on your hardware - quintessentially your CPU.

For example, on certain Intel CPUs - especially the Duo Core (Celeron) series, it does not support VT-x technology, and also does not support EMT64 technology, thus you are limited to running only on a single core, and 32-bit guest OSes.

Check your processor, the defining factors are there.

Intel Processor Spec Finder

Solution 2:

Yes. Although, you need your BIOS to support virtualisation extensions