Windows Version Maximum Physical Processor Limit Maximum Logical Processor Limit Windows XP Home Edition 1 2 Windows XP Professional 2 4 Windows Server 2003, Standard Edition 4 8 Windows Server 2003, Enterprise Edition 8 16 Windows Server 2003, Datacenter Edition 32 32 I looked long for this info and thought I'd share it Re: Windows software version and # of supported physical vs. logical processors. That is HT or Dual-Core. HT and Dual-core = 1 physical processor as recognized by windows. For instance XP Home = license for one physical CPU and 2 logical (that is one HT cpu or one dual-core CPU) XP Pro = 2 physical 4 logical Server = 4 to 32 depending on version. Hope this helps somebody with their set-ups.