Windows Server 2003 x64 - Processor Support Supports up to 4 (x64 architecture-based computer with Intel Pentium or Xeon family with Intel Extended Memory 64 Technology, or AMD Opteron family, AMD Athlon 64 family) Windows Server 2003 Enterprise x64 Edition - Processor Support Supports up to 8 (x64 architecture-based computer with Intel 64-bit Xeon, 64-bit Pentium, AMD Opteron, AMD Athlon 64, or compatible processor) Windows Server 2003 Datacenter x64 Edition - Processor Support Support up 64(x64 architecture-based computer with Intel Pentium or Xeon family with Intel Extended Memory 64 Technology, or AMD Opteron family, AMD Athlon 64 family, or compatible processor) x32 Editions listed below.