Windows 2008 Versions - Hardware Support

Below I will list the different versions of server 2008 and what each support in terms of hardware.

Server 2008 Web Server x86 supports 4GB Memory and 4 processors
Server 2008 Web Server x64 supports 4GB Memory and 4 processors

Server 2008 Standard x86 supports 4GB Memory and 4 processors
Server 2008 Standard x64 supports 32GB Memory and 4 processors

Windows 2008 Enterprise x86 supports 64GB Memory and 8 processors
Windows 2008 Enterprise x64 supports 2TB Memory and 8 processors

Windows 2008 Datacenter x86 supports 64GB of Memory and 32 processors
Windows 2008 Datacenter x64 supports 2TB of Memory and 64 processors

Windows 2008 Datacenter can only be purchased OEM.