I'm amazingly out of the loop with modern x86 processors (my laptop has a 2008 Core 2 Duo, my desktop has a 2009 Phenom II, and I have not yet felt a need to up

I'm amazingly out of the loop with modern x86 processors (my laptop has a 2008 Core 2 Duo, my desktop has a 2009 Phenom II, and I have not yet felt a need to upgrade) so I gotta ask: what are the issues with supporting a new iteration of an Intel CPU on an OS level? Isn't a generic x86 CPU a generic x86 CPU that runs anything you throw at it anymore?