What are the advanatges and desadvantages of vista X64?

[yetyhunter]

I know that vista 32 bit supports only 4GB of total system ram and vista 64 bit supports allot more.I'm planing to upgrade to 4 GB of ram.My total system ram will be 512x2(8800 GTS 512 SLi) + 4Gb=5 GB. Vista will only see 3 gb + 1gb video.
So i'm planing to upgrade to vista x64.What is the bad side of vista x64?Is this upgrade even worth it(performance wise)?
Will vista X64 support games and software like the 32 bit version?

 

[Scotteq]

Read:
Why 64 bit Articles:

http://www.extremetech.com/article2/0,2845,1857478,00.asp


http://www.anandtech.com/gadgets/showdoc.aspx?i=3034

http://www.anandtech.com/cpuchipsets/showdoc.aspx?i=3044

http://www.anandtech.com/systems/showdoc.aspx?i=3060

V64 Questions and Answers
http://blogs.zdnet.com/Bott/?p=511