Well, no doubt I'm totally wrong, but I thought that the BIOS was only active on its own for the first few seconds after the computer is switched on. It tells the other bits which drive to boot from and which sector of the disc to read and how to do so. Then the disc based OS is read and the first section is run. It is this that takes the time. In the days of Win 98 the full desktop only appeard when the system was ready to run. In the case of XP, said desktop appears befoe the OS is fully loaded - a trick by Microshaft to kid people that the booting time was less than it actually was.
If the Bios loading time can be improved from - say 2 seconds to 1, I can't see it making much difference, but I am sure someone more knowledgeable will pop along to state why I am wrong!
P.P.