Microsoft is moving to 64-bit processors as it announced its new Exchange 12 e-mail server will solely run on 64-bit processors.
By late next year, Microsoft expects to deliver Exchange 12, which will run only on x86-compatible 64-bit servers, said Bob Kelly, general manager of infrastructure server marketing at Microsoft.Longhorn Server R2 and a small-business edition of Longhorn Server will also be available only for x86 64-bit processors as well as the Centro bundle. More info over here.
Kelly said 64-bit chips will make the greatest impact on the performance of applications such as Exchange and its SQL Server database.
"IT professionals will be able to consolidate the total number of servers running 64-bit (processors) and users will be able to have bigger mailbox size," he said.