The upcoming Windows 8 operating system is shooting to minimize a computer's memory usage through efficient design so it can run on hardware originally designed for Windows 7. This will allow you to keep your current Windows 7 hardware if you decide to upgrade.
This memory saving is accomplished by several methods. The first way is by combining memory which allows Windows to identify duplicate memory being used for identical tasks and then retain a single copy. If a program etc needs some freed up memory, Windows provides what's called a private copy. This process can make anywhere from 10s to 100s of megabytes available. Windows 8 will also move some services to a start on demand model saving even more memory. One other thing Microsoft has done is removed 13 different services and has changed a number of others from automatic to manual
These tweaks will also allow for longer battery life for Windows tablets and phones that don't hold much physical RAM. This is necessary because Windows 8 will be running on these devices as well.