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Exchange Server 2007: 32-bit versus 64-bit hardware contributor Serdar Yegulalp explains your 32-bit and 64-bit options for Exchange Server 2007 and offers warning about an important installation caveat.

When Microsoft announced that Exchange 12 -- or Exchange Server 2007, as it has been officially christened – will only be a 64-bit product, there were groans of dismay, but also a great many grunts of assent.


64-bit hardware is gradually becoming the preferred norm for server-level software, partly because it has become readily available at decent prices, and also because of the server scalability and performance it offers.

But now it seems there will be both 32-bit and 64-bit editions of Exchange Server 2007. That's prompted some IT administrators to ask: Is 64-bit Windows required for Exchange Server 2007?

If you're putting Exchange Server 2007 into a production environment, it absolutely is. If you're just using Exchange Server 2007 for testing or teaching, and you're not putting it under production loads, it is not.

The 32-bit version of Exchange 2007 is essentially a test-and-evaluate edition, so it has not been tuned for production loads, and is not supported by Microsoft as a production-environment application.

Jim McBee has discussed some of the differences between the 32-bit and 64-bit editions of Exchange Server 2007, and the single biggest disparity he has identified is memory usage.

More on Exchange 2007 and hardware management:
Microsoft delivers Exchange Server 2007 public beta

The 64-bit push is on for Windows and Exchange shops

Best Practices: Optimizing Exchange disk performance

Step-by-Step Guide: How to spec your Exchange hardware needs

Exchange 2007 Reference Center

Exchange Server Hardware Management Reference Center

64-bit applications can directly access more physical memory than their 32-bit counterparts. More physical memory available to Exchange Server means less blocked I/O, and less paging or swapping to disk when activity is high.

This translates into better performance, and better use of the hardware that Exchange Server is installed on.

One important caveat: Do not attempt to install the 32-bit version of Exchange 2007 on a 64-bit edition of Windows Server 2003.

32-bit applications are run in 64-bit Windows through an emulation layer; Exchange Server 2007 will not work through that layer. Use the full 64-bit edition whenever you can, and reap the rewards it'll provide.

About the author: Serdar Yegulalp is editor of the Windows Power Users Newsletter.


This is great news for those of us who use Exchange Server in very small environments and wish to keep our skills up. However, it leaves a great deal open to question, such as:

  • Can I mix the 64-bit and 32-bit versions in the same organization?
  • Is this using the beta or evaluation copy of Exchange Server 2007?

Currently, I have Exchange Server 2003 running. I have taken a few steps to prepare for Exchange 2007, but I only have one 64-bit server. My primary mailbox server (a Dell 1750) can only support a 32-bit operating system.

I realize, in the end, that I will need to ultimately upgrade the hardware to all 64-bit, but this seems to offer an upgrade path without immediately requiring hardware purchases.
—Dan M.


So where do we download the 32-bit version of Exchange 2007? I can't seem to find it.


The 32-bit version of Exchange 2007 is only available in the MSDN edition of Exchange, since it's not meant to be used commercially but only in a development-and-testing environment.

Your best bet is to get the MSDN Premium subscription (with some version of Visual Studio). You can get more details about which MSDN and Visual Studio 2005 subscription to use to get the Exchange 2007 32-bit edition. "Visual Studio Professional with MSDN Premium" appears to be the lowest tier that includes Exchange Server.
—Serdar Yegulalp, tip author

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