I have installed Windows 8.1 Preview on an Intel-DG33FB-based PC. The O.S. installed beautifully, but there is a yellow exclamation in Device Manager, under Unknown Devices, next to a "PCI simple communication device." This obviously refers to the Intel Management Engine Interface, which is no longer listed anywhere in Device Manager. The I.M.E.I. has no Windows 8.1 driver and none can be installed. I contacted Intel customer support. After several days of silence and not before a message to their C.E.O. I received the following reply from "Andre B." of Intel customer support:
Please take note of the fact that the board DG33FB is out of interactive support (EOIS) as stated in the notice on following webpage: http://www.intel.com/p/en_US/support/highlights/dsktpboards/dg33fb Intel will therefore no long provide support for the DG33FB board, and no new drivers will be developed for this board. [...] Windows 8.1 preview is not a production version of Windows. Drivers are provided for production versions of validated operating systems, I regret to inform you that Intel does not provide support nor drivers for non production versions of operating systems.
I would not install Windows 8.1 Preview or any other version of Windows 8.1 on any computer system that has any Intel hardware in it until such time as Intel has released all its drivers for this operating system.