Microsoft have just released the Windows 8 Hardware Certification Requirements for Client and Server Systems.
The device begins with:
Certified Devices in Systems
A Windows Certified System is composed of Windows certified components. These internal devices are certified before system integration, leaving the focus of system testing on those features which require the coordination of multiple components or configuration settings unique to the system under test.
At the system certification level, if the system includes a device or component, then all the requirements associated with that device as exposed to Windows must be met. We encourage a review of the requirements for each system components incorporated into the design of a system.
If Implemented Requirements
The Windows Hardware Certification program declares requirements which must be met by any system under the feature area of system fundamentals. Additional functionality is built into Windows which is optional, and can offer a competitive edge for manufacturers should they chose to implement these features.
In these cases, there are requirements which must be met only if the additional functionality is implemented. Because these additional requirements apply only if the relevant functionality is implemented, they are referred to as “if-implemented” requirements in this document.
The Hardware Certification Kit detects features exposed by a product automatically. The detected features the will be tested for compliance whether they were mandatory to successfully be certified as a defined product type or if the feature is optional. The title of the requirement or the exception field will indicate when a requirement applies.
You can download the Windows 8 Hardware Certification Requirements for Client and Server Systems here.