Insert your pen-drive. Let your PC read it.(Minimum 2 GB)
Right click on My Computer.Click on Properties from context menu.Click on Advanced tab.Click on Settings under Performance.Click on Advanced tab.Click on Change button under Virtual memory.Select your USB drive.Click on custom size radio button and give the values as follows;Initial Size:1020Maximum size:1020The size depends upon your free memory capacity of your pen drive. So you can change this limit according to your pen drive size.Click on Set button, then click on OK.Now you have to restart the computer. The speed of your computer will be increase
For Windows 7
Plug in your pendrive-> Format with NTFS or FAT32Now go to properties->Sel ect ReadyBoostCheck Use this device->Choose maximum space to reserve system speedClick on Apply and OK. Your readyboost PenDrive is ready Now to Use.Here is an personal suggestion HP and Sandisk is the Best for this work so what are you waiting for.
