Vista 64 and 4GB memory

[UniqueID]

i am not tottally understanding the point of having vista x64 coupled with 4gb memory.. i'm sure there is some benifical point to doing it but i can't find out what it is anywhere.
anyone care to give it a stab in the dark for me?

 

[UniqueID]

and the min after posting he finds the answer;
http://www.crucial.com/kb/answer.aspx?qid=4251

but if anyone else can add to this feel free

 

[Biffa]

Its actually the other way round, if you have something that needs 4GB of RAM then you need Vista64 because without 64bit addressing you won't see all of it.