By default most operating systems install the environment under the BIOS system. This is a legacy system which has worked very well, however the limitation of BIOS is 2TB. This means that as hard drives go beyond the limit of 2 TB Windows operating system wouldn’t recognise the remaining drive space.
BIOS If the server has a 3 TB disk, only 2 TB will be usable by the server the remaining 1 TB will be listed as unallocated space. UEFI Under this environment if the server has 3 TB disk, all 3 TB will be usable by the server.
The activation of UEFI requires the motherboard to support UEFI in the first place, most new servers will support UEFI mode or DUEL mode which consist of both BIOS and UEFI at the same time. The installation is the same as any windows however the installer will be invoked from: \EFI\BOOT\BOOTX64.EFI.