Question Ready Boost. What does it do?

[box o rocks]

Does it use the flash drive to give you extra system memory? Or does it use the flash drive to cache the HDD to make stuff load faster? Or what?

 

[rgd1101]

https://en.wikipedia.org/wiki/ReadyBoost

 

[box o rocks]

https://en.wikipedia.org/wiki/ReadyBoost

So... is this a persistent cache? Will the data be available at the next boot to make Win load faster?