Microsoft announces that Exchange 12 will be 64-bit only

This is actually old news now, but at the Microsoft IT Forum 2005, Microsoft confirmed some rumors that have been floating around that Exchange 12 will be 64-bit only. So, yes, the decision has been made that Exchange 12 will run only on a 64-bit platform; there will NOT be a 32-bit version of Exchange 12. Microsoft is in a precarious position of delivering improved support for some of their clients and delivering a stable platform for all customers. I'm afraid that supporting two different platforms may make the product much more difficult to be supported.

Microsoft has taken some heat in the industry from pundits like Ed Brill as well as the media on this decision, however I'm not so sure this is a bad thing.

• Most of the server-class hardware that is shipping today is already capable of running Windows 2003 64-bit operating systems. That, unfortunately, does NOT include equipment in my own lab. So before betas start shipping I will need to get my hands on some 64-bit gear if I'm going to do any testing. :-(
• The inital performance testing on the early versions of Exchange 12 running on 64-bit hardware found a 75% performance improvement in I/O when compared with the 32-bit version. This is pretty dramatic considering that most Exchange bottlenecks now (after you toss 4GB of RAM and 4 CPUs at a server) end up being I/O.
• Exchange 12 will probably not be available anytime before mid 2007. By that time, most organizations that have done a hardware refresh will have 64-bit hardware.
• Most of the time, organizations that upgrade from an older version to a newer version upgrade their hardware platform at the same time they upgrade the application.
• Hopefully the information store service will be completely re-written to overcome some of the memory limitations on that platform (right now it cannot access over 2GB of RAM).
• The announcement now will ensure that 3rd party vendors such as antivirus and backup vendors get their 64-bit products ready for shipping sooner rather than later.

I think by the time Exchange 12 ships, this will all have blown over and the industry will be much more likely to embrace 64-bit applications.