There really haven't been many major changes to the x86 architecture since the 386
CPU architecture is hardly all that matters to the core OS
Pretty much everything else should be handled with driver updates or at worst a service pack.
Driver updates work fine for adding support for a new model of graphics card, but when you introduce a whole new kind of device (e.g. WiFi, SSD) the implications reach into the OS itself. They managed WiFi in a service pack for XP, but it was both a pretty unprecedented level of change for a service pack, and always felt kind of tacked-on.
CPU architecture is hardly all that matters to the core OS
Pretty much everything else should be handled with driver updates or at worst a service pack.
Driver updates work fine for adding support for a new model of graphics card, but when you introduce a whole new kind of device (e.g. WiFi, SSD) the implications reach into the OS itself. They managed WiFi in a service pack for XP, but it was both a pretty unprecedented level of change for a service pack, and always felt kind of tacked-on.