It's true, the all new Windows Vista supports this concept and would let you make your usb pen drives or removable storage media act as an extra Random Access Memory (RAM) which would help you in increasing your system speed.

Adding RAM to the system is one of the best ways you can improve your system performance. However, adding additional RAM can be a costly affair for some people or hardware limitations such as not having enough slots to plug another one can be disheartening .

The geniuses at the Microsoft have came up with a great idea called Ready Boost, which makes it possible to use your USB Pen Drives or Removable Media act as an additional memory to the system, thus enhancing your system's performance. Surely this concept was there since long with some applications allowing you to create RAM Drives, but RAM drives really didn't helped with Operating System Task Scheduling or other internal OS tasks.

Ready Boost works with because of intelligent memory management of Windows SuperFetch which can significantly improve your system's responsiveness. Your plugged-in and configured ReadyBoosted USB device serves as an additional memory cache for the OS. It is just like adding another physical RAM to the system.

Steps to make your USB Device act as an Additional Memory

1. Insert your USB device into your computer's USB Port.

2. Once the device is detected and appears as a removable drive in windows explorer, right click the drive and click properties.

3. Goto the ReadyBoost tab, and click Use this device. Allocate as much space as you could using the slider below.

4. Click apply!

That's it, your USB Pen Drive or any other Removable Media would hence forth help your system be faster and more responsive.