Do Macs run the full Windows OS making full use of Windows functionality?
There are basically two ways you can run Windows on a Mac.

You can run Windows in an emulator like VirtualBox, Parallels or VMWare. You get the entire functionality of Windows, but it is running within a VM on another operating system so you don't get the entire performance of the Mac as the resources are shared between Windows and OS X.

But you can install Windows directly on a Mac with the help of Boot Camp. When you do this you are running Windows directly on the Mac hardware and get the entire functionality of Windows with all the performance of the hardware as OS X isn't involved.