It seems we have some badly worded docs on some Microsoft sites that may lead you to believe that you cannot run Exchange 2003 on x64 bit systems. Also the release notes seem to be in error as well...
Published Nov 18, 2005
Version 1.0
Blog Post
Mike,
I am not 100% sure I understand your question but:
E12 will NOT run on IA64 at all. It will run on x64. Additionally, seeing that clustering relies on MS Clustering Service, which is not present on non-Enterprise Windows, Enterprise is required for clustering to work.
Here is more on the E12 and 64 bit story:
http://blogs.technet.com/exchange/archive/2005/12/29/416613.aspx
I am not 100% sure I understand your question but:
E12 will NOT run on IA64 at all. It will run on x64. Additionally, seeing that clustering relies on MS Clustering Service, which is not present on non-Enterprise Windows, Enterprise is required for clustering to work.
Here is more on the E12 and 64 bit story:
http://blogs.technet.com/exchange/archive/2005/12/29/416613.aspx