[Vista] What does Vista do when it Sleeps?

I have to say the new "power button" which puts Vista into the new "Sleep" mode seems nice. My 2 Ghz laptop (which doesn't have much on it yet I must admit) goes to sleep in 1 second and starts up in pretty much the same time. Superfast - I like it.

As I understand it, by default a laptop is put into sleep mode when the power button is pressed, then goes into hibernate (saves memory to disk) after a few hours or so, to save power. When resuming from hibernate it takes a bit longer for the box to get going, but that's understandable. It's possible to configure what happens when you press the power button or close the lid, also depending on if you're on battery or plugged in.

You can read more of what Vista does when it's in sleep mode on the Microsoft Vista Performance pages.