Bios Mods -The Best BIOS Update and Modification Source

Hello all
I'm trying to modify the bios of an old hp notebook to install a new and faster wireless adapter. I've found a tutorial on the internet, but I have a concern:
If I open the bios file with Phoenix bios editor and save a new file without any modification, I expected a new file identical to the original, but if I compare the two files (with fc /b) they are totally differents. Why?Is it correct?
If can be usefull, i tried with both XP and win7@64 and phoenix bios editor pro 2.2.1.3; the notebook is a HP dv 6723el (centrino duo) with the last available bios.

Many thanks

Adriano

That's just Phoenix tool using LZMA compression to compress all the modules in a slightly different order than the manufactures do. All the modules still have the same unique id and are loaded into ram at their specified locations. Nothing to worry about

Many thanks for your reply.
As soon as I receive the new adapter I try.
regards

Adriano