Computer resources as in hardware? Yes, it can. Otherwise, you
will be buying 3 PCs if you need all of them to be up at the same
time.
I don't know of any ways that you can do multi-boot in the same
session in the same PC without some form of virtualization.
But on the software side, it will definitely have some impact on
the resources usage of the host OS. Depending on the type of
virtualization implemented, they will have different impact.
If you implement VMWare or other VM software, it will take up
quite a lot of resources. Something like Xen hypervisor will not
have the same impact.
