Description
ReadyBoost is a component of Microsoft Windows that works by using flash memory, USB 2.0 drive, SD card, CompactFlash or any kind of portable flash mass storage system as a drive for disk cache. ReadyBoost is also used to facilitate SuperFetch, an updated version of Windows XP's prefetcher which performs analysis of boot-time disk usage patterns and creates a cache which is used in subsequent system boots.

Just thought I'd mention this:

ReadyBoost is dependent on the SuperFetch component and there is no way to get it working until we can solve that. So everyone should keep an eye on the SuperFetch thread for the time being