DOS users are familiar with the speedup technique of copying ROM BIOS code into
RAM where it executes significantly faster, speeding operations – particularly
screen updates. Many computers support this feature. Don’t enable it if you are
running NT because NT reads the BIOS at boot and does not use BIOS functions
afterwards. Once NT is loaded, it does not use BIOS functions. NT uses virtual
device drivers instead. Implementing BIOS shadowing when you are running NT is
RAM wasted.