Let say, you have more than 4 GB RAMs and Windows Vista 32 bit could use less than 3 GB, 1 GB will be wasted. Vista 64 will take care this RAM issue but unfortunately, your notebook or hardware vendor doesn’t supply it (such as Izzi broadband). So, how to solve this problem?
Good news that, Windows Server 2008 (32 bit) support more than 4 GB RAMs and has no issue with Vista tailored driver. Windows Server 2008 simply accept Vista driver without any fuss. More good news? You can download Windows Server 2008 (32bit or 64bit) from Microsoft website (for free) and they let you evaluate it for 240 days (8 months) legally.
http://expertester.wordpress.com/2008/08/07/how-to-get-windows-server-2008-for-free/