Why does windows 7 64bit require more disk space and more RAM?
http://windows.microsoft.com/systemrequirements is where I got the information.
Windows 64 Bit includes several programs in both 32bit and 64bit versions (like Internet Explorer). This is one reason for the higher disk space requirement. The RAM is probably due to similar reasons and that the 64bit pointer just requires twice as much space.
64 bit applications use larger variables and thus need more RAM.
As for the space requirement, Windows installs both 32bit and 64bit versions of it's default applications like Internet Explorer.