If you upgrade a computer with more than 4 CPUs from Windows 2000 Server to Windows Server 2003, you receive:
Exceeded Processor Count
You have more CPUs installed in your machine than this version of Windows Server supports.
If you upgrade, one or more processors will be disabled.
For more information about processor restrictions in Windows Server, see the Microsoft Web site at http://www.microsoft.com/.
Setup then quits.
If you do a clean install of Windows Server 2003, setup completes without any warning, but some processors are NOT supported.