disabling every unused feature/interface in bios

hello, im not a complete noob with pcs, but i dont know a great deal about the bios and stuff, and i read somewhere that you should disable every feaure or interface, they mentioned: secondary NIC's, serial ports, parallal ports" as they use system resources.
i don't have a clue what any of those things mentioned are, but sinse im about to disable onboard sound, i could quickly run through and disable all the stuff that isn't needed, like this person says.
Only problem is, i dont know what is needed and what isn't.
so i was wondering, how i would go about finding out which bios features i dont need and can safely disable?

thanks for your time.