ReadyBoost feature is the MS Windows
7/Vista feature that allows you to use a USB flash drive as virtual memory(ReadyBoost) in order to enhance the performance. There you can get the additional information about ReadyBoost:
How to mount ReadyBoost drive:
Insert your USB 2.0 flash drive (min. 256M, max. 4GB) in USB port. Open up Computer, mouse right-click on the drive that you want to use as ReadyBoost drive and choose Properties. Select the ReadyBoost tab, click Use this device. Optionally choose how much of the device to use.