Oh Windows why do you only support 4GBs !!WHY!!

Vista now supports 4GB of memory with SP1, or so you think.  Check out these nice graphic friendly articles on why that is not true.
 
http://www.codinghorror.com/blog/archives/000811.html
http://www.digitmemo.com/articles/30/windows-and-4gb-ram-the-frustration-confusion-and-solutionpart-3/
http://4sysops.com/archives/why-windows-vista-only-sees-3gb-memory-in-a-pc-with-4gb-ram-and-how-vista-sp1-fools-its-users/