The most significant differences in hardware support come from the IA64 versions of Windows Server 2003. This includes the following:
New memory architecture to support a larger address space
Support for 64-bit device architectures such as PCI-X (this support is also included higher-end IA32 systems)
Improved drive partitioning using GUID Partition Tables (GPT) rather than legacy Master Boot Record (MBR) partitioning
Application interoperability using the Windows32-on-Windows64 (WOW64) emulator
Registry and system file interoperability so that 32-bit and 64-bit versions of the same applications don't conflict with each other
Beyond the support for an entirely new platform, the watchwords for hardware support in ...