Si, si può fare ed è supportato. Ma è sconsigliato fortemente. :) Ecco perchè: Using a mix of 32-bit servers and 64-bit servers in a server farm is supported. However, this scenario is not recommended because of the potential performance issues that could occur. For example:
With a clustered front-end Web server that uses round robin, the 32-bit server will be the bottleneck.
If a 64-bit front-end Web server is making calls to a 32-bit SQL Server database, there may be a bottleneck if SQL Server does not have adequate resources. This also applies to a 64-bit indexer that is working against a 32-bit SQL Server database.
If circumstances require a heterogeneous server architecture, we recommend that you use homogeneous (32-bit or 64-bit) servers on each application tier, for example, 32-bit servers for all the front-end Web servers. Tratto da: Determine hardware and software requirements (Windows SharePoint Services) http://technet.microsoft.com/it-it/library/cc288751(en-us).aspx Lo stesso vale per Moss 2007: Determine hardware and software requirements (Office SharePoint Server) http://technet.microsoft.com/en-us/library/cc262485.aspxUPDATE:Advantages of 64-bit hardware and software (Office SharePoint Server 2007): http://technet.microsoft.com/en-us/library/dd630764.aspx