Insert your USB stick 
First, make sure that you have your choice of removable  flash memory to hand. To start the ReadyBoost process, you  need to insert your USB stick into your computer and wait for  the AutoPlay menu to appear. If you’re opting to use an SD card  instead, just place it into the slot on your laptop or desktop PC,  or use an external card reader.
Choose ReadyBoost 
Once the AutoPlay window pops up, you can start using  ReadyBoost. The relevant option appears at the bottom of the list,  where you’d normally choose to either browse the device or load  images from an SD card straight into Windows Live Photo Gallery.
 When you click on the ‘Readyboost’ option, you’ll be taken  straight to a configuration screen. 
Create a dedicated device 
If you’re planning on using this USB flash drive just for  ReadyBoost and don’t intend to store any data on it as well, you  should turn it into a dedicated device. To do this, simply check  the second option in the list, ‘Dedicate this device to ReadyBoost’.
 This option makes all of the USB drive’s storage space available to  be used by Windows. 
Prepare it for use 
Now that your USB stick is a dedicated device, it’s ready  to give your computer the performance boost it so badly needs.
 Click ‘OK’ and your device is prepared for use by the system. From  now on, whenever you insert that drive into your PC, Windows  recognises it and adds its capacity to the system, so your  computer has more memory to use 
Partition a USB device 
If you still want to be able to use your USB stick’s memory  for storing your documents, photographs and other files, but  you also need to speed up your computer, a different option is  required. This will have a less dramatic effect than making it a  dedicated device, but can still be helpful. Insert your USB stick or  SD card and click the ‘Speed up your system’ option as before 
Slide to increase 
You can use the slider to allocate a portion of the disk’s  space to ReadyBoost, while still leaving a certain amount of room  for your files. Move the slider left or right until you’re happy with  the amount of space. We wouldn’t recommend dedicating less  than 256MB to ReadyBoost, otherwise you won’t see much  difference in the speed of your system. 
Double up 
In Windows Vista, ReadyBoost only supported one device  with a capacity up to 4GB, but with Windows 7 or 8 you can use  multiple fast devices, with nearly unlimited memory. If your  laptop or desktop computer has an SD card that’s unused for  the majority of the time, why not consider making this a semipermanent ReadyBoost slot? 
Enjoy! 
You should now have a noticeably more responsive  computer, and be able to perform daily tasks faster than before.
 Although Readyboost won’t help you transform a basic machine  into a gaming behemoth, you should feel a real change in your  system’s performance, and it might even stave off the need for a  new computer for a little while to come.