根據微軟官方說法是這樣的：
Windows Features on UEFI
Because of the widespread availability of 64-bit hardware, the capabilities that UEFI offers, and the rapid transition to UEFI firmware, Microsoft has chosen to implement all new firmware-related features on UEFI systems first. Microsoft will evaluate the possibility of additional architectural work to support new features on older BIOS systems on a case-by-case basis.
看來只是想不想做的問題而已。
原始文件如下：
http://msdn.microsoft.com/en-us/win...e/gg463149.aspx