Rapid Boot is a feature introduced by Lenovo for their laptops. It allows the system to skip unnecessary boot parameters, files and options to load the operating system faster. The feature was first used for ThinkPad T420s model but soon was made available to most of their laptops.
In order to enable this feature, you first need to install the utility which is found on the Support CD that arrived with your laptop or from the Support website available for your product. After you install it, you can enable the feature from the Control Panel using the provided utility. Then restart the laptop and enter Bios and navigate to Startup tab and from Boot mode choose Rapid and restart your laptop.