What's the difference between WARP drivers,reference drivers and software drivers?

Question

In DirectX 11, there are four types of drivers:

• D3D_DRIVER_TYPE_HARDWARE
• D3D_DRIVER_TYPE_REFERENCE
• D3D_DRIVER_TYPE_SOFTWARE

Answer 1

Reference device and Software device http://www.gamedev.net/topic/631456-whats-the-difference-between-d3d-driver-type-software-and-d3d-driver-type-reference/

For WARP device http://msdn.microsoft.com/en-us/library/gg615082.aspx

Reference device is provided as pre-release in general (so people can start to write code using full featured api without having hardware support yet), the problem being that reference device (and anything but hardware really) is so slow it's mostly unusable.