Windows ReadyBoost can use storage space on some removable media devices, such as USB flash drives, to speed up your computer. When you insert a compatible device, the AutoPlay dialog box will offer you the option to speed up your system using Windows ReadyBoost.
Plug a flash drive or other removable media device into your computer. This should automatically open AutoPlay.
If AutoPlay does not open, it might have been disabled. For more information, see Troubleshoot AutoPlay problems.
Under General Options, click Speed up my system.
This will display the Properties dialog box for your flash drive or other removable media device.
Click the ReadyBoost tab, and then do one of the following:
To turn ReadyBoost off, click Do not use this device.
To turn ReadyBoost on, click Use this device, and then move the slider to choose how much of the available space on your flash drive you want to reserve for boosting your system speed.
The removable media device must contain at least 256 megabytes (MB) of space to work with Windows ReadyBoost.