Creating a dual-boot system will let you safely test Windows 10 Technical Preview using the full power of your PC’s hardware alongside Windows 8.1. In Windows 10, Microsoft is doing something differently as it’s letting customers download and install versions of the operating system early on, so users get a sneak peek of what is to come. But also it helps Microsoft to get more feedbacks and design an operating system that people will actually like.
However, because the operating system remains an unfinished product, it has numbers of bugs, and there are many features that don’t work. As such it’s not recommended to use it as your primary operating system.