What is Windows DreamScene, and how does it affect my computer's performance?
One of the attractions of Windows Vista Ultimate Edition is its Ultimate Extras that are made available via Microsoft Update. These Ultimate Extras offer additional functionality, such as improvements to BitLocker Drive Encryption, a poker game, and DreamScene, which lets you configure a video (.mpeg or .wmv format) to be used as your desktop background instead of a static picture, provided your computer has the power to handle the Windows Aero UI. The list of Ultimate Extras is available at http://windowsultimate.com/Blogs/Extras/Default.aspx and will grow as Microsoft develops more "extras." The programs are available via Microsoft Update or the Windows Ultimate Extras section of the Vista Welcome Center.

If you install DreamScene and choose to use a video as the desktop background, the amount of CPU and memory utilization will vary according to the video selected. When I used a video as my desktop background, the Windows Explorer process showed about 15 percent more CPU usage on a dual-core AMD 4400+ processor and showed that it used 50MB of memory. Although the amount of memory that the feature uses isn't a big problem, the processor hit might slow down certain functions. WMV files use heavy compression and therefore use more CPU than MPEG files use, so consider that when selecting a video. You also need to consider hardware because graphical processing units on some machines can take over the MPEG processing, and therefore the machine uses less CPU. You can also download a DreamScene add-on from http://dream.wincustomize.com that gives you access to many .dream files that you can use on your machine.
—John Savill