Most all of the new computers that are larger than a laptop have the capability to subdivide themselves into multiple computers. These "virtual machines" can have different processor and memory configurations than the host computer. What makes this useful? The usefulness lies in the server and networking arena where the configuration is simplified with several special purpose servers rather than a single monolithic do-everything server.
For instance, for my humble operation, I have up to 4 virtual machines running: a phone pbx server, an applications server, a test server, and a Windows 7 virtual machine. The phone server is not cluttered by any extra software that might cause problematic interactions and the test server is where I do my software evaluation so as not to impact my mission-critical applications server. All of these exist in a single "real" box.
Where else do we find these machines? Amazon and Rackspace both sell all sizes of these machines as a service. You can rent a machine for literally pennies a minute. If the initial machine selected is too small for the task, then rent a bigger one. These companies make it possible to rent a tiny part of their immense architecture in an affordable and scalable manner. I have used both companies and I am a satisfied customer of each. So welcome my friends, welcome to the machine(s).