The Longhorn server OS part got it system requirements. The beta 3 is out and it will need a minimum a 1 GB memory but Microsoft recommends the 2GHz and says it is optimal if you have 3 GHz. Windows Server "Longhorn" for Itanium-based Systems needs an Itanium 2 CPU.
You can install it with a minimum of 512 MB of memory, while 1GB is recommended. Optimum is 2 GB for the full installation, or 1 GB for the server core installation.
The maximum amount of memory you
can install is 4 GB for the standard 32 bit version, while the enterprise and
Data center 32 bit supports up to 64 GB. The maximum for the 64 Bit
version is 32 GB for Standard 64 bit or 2Terabyte (2048 GB) for the Enterprise,
Data center or Itanium version.
You need a minimum 8GB of space and for the full installation you need the 40 GB. The core server installation takes about 10 GB. Microsoft says that the optimal for full installation is 80 GB. Computers with more then 16 GB of memory will require more disk space for paging, hibernation and dump files.
The Vole recommends you have DVD-Rom, Super VGA 800x600 or higher display, and keyboard and mouse.
You need to be the part of the Technet or MSDN to get this beta.