Fast sleep and resume
This feature is included in the following editions of Windows Vista:
In the past, if you turned your computer off to save power or extend your mobile PC's battery life, it took a long time for it to start back up when you wanted to use it again. With Windows Vista, you can easily and quickly use your PC whenever you want, while still preserving battery life. The default "off" state is now the new Sleep power state. Just press the power button on the Start menu or on your PC, and your PC will automatically save your current session to memory, and then quickly enter into a very low power state. It will also save your session to the hard drive, so you can access it even if the memory loses power. Then, when you want to resume your computer use, just press the power button on your PC. Your PC will turn on in seconds, and be just how you left it last time.
Putting your PC to sleep can save time and power, and protect your work.
Unlike Windows XP, which offered the different Standby and Hibernate modes, Windows Vista combines the benefits of both modes into Sleep to simplify the entire process for users. For optimal speed and performance when putting the PC to sleep, and when resuming it, purchase a new PC with Windows Vista preinstalled, rather than upgrading an existing PC.