Microsoft recently informed the NVMe community the Windows 8.1 and Windows Server 2012 R2 inbox drivers now includes Boot Support for NVMe devices in windows.
The driver, StorNVMe.sys, was designed primarily with the enterprise in mind, but is extensible and flexible enough to grow into the client space. The ability to boot from NVMe devices on Windows 8.1 and Windows Server 2012 R2 using the Windows inbox driver requires the platform to have the appropriate BIOS support and the device is not an eDrive implementation.
NVM Express (NVMe) thanks Microsoft for their continued NVMe support in delivering capabilities customers need.