PCI was Plug & play by design. A PCI BIOS will assign resources, but
   the PCI cards don't care what resources they get. Often, the PCI cards
   end up in unusual I/O spaces (like above the 3FF range of the original
   XT).
   
   Some PCI cards have hard-wired resource requirements (like video
   cards), but the newest video cards are beginning to wean off that
   requirement, as games stop depending on VGA and use DirectDraw under
   Win95. Cases include the on-board video that some SIS motherboard
   chipsets provide.
   
   As per ISA PnP, The BIOS keeps its PCI config info in its NVRAM, and
   Win95 keeps a copy in the Registry.
   

Some parts © 2009 Advameg, Inc.