Dreamscapes leverages the 'DreamScene' Ultimate Extra available free to all users of Windows Vista Ultimate. This technology enables high-resolution videos to be applied as wallpapers which is natively supported by Windows Vista Ultimate.

The videos aren't limited to your personal collection Stardock offers an ever-growing library of DreamScenes where you can find many mesmerizing dreamscenes such as Desktop Earth! DreamScapes supports Microsoft's DreamScene ".Dream"
format which uses WMV or MPEG clips. DreamScape adds on additional
stuff such as dynamic content, new functions and author info. It can build customized wallpaper 'animations' and automatically change your wallpaper according to what your machine is doing!

With this, expect a broad 5-20 percent overall hit on your processor cycles as well as RAM utilization. The current version works only on Vista Ultimate, but a new version should be out soon, and promises to work on all versions. XP users can find a DreamScene version still under beta