Change log for Vista SP1:
http://www.istartedsomething.com/20071208/vista-sp1-changelog/
Notice the 32-bit will be able to address a full 4 gigs of RAM.
http://www.istartedsomething.com/20071208/vista-sp1-changelog/
Notice the 32-bit will be able to address a full 4 gigs of RAM.