How many Core's are supported by Windows XP Pro

Hi,

maybe i'am not in the right forum, however, i was asked by an customer how many cores will be supported in the furture by MS WIN XP Pro.

I searched the MSN site and only found an Licensing related Document, it suggests that the number of supported Processor Cores are not limited, only the number of sockets are limited.

I'am still searching for such an document, or at least an clear statement how many Cores can be handled by Windows XP Pro, Windows 2000 and Windows Vista.

I would be glad if anyone could help me!