Exchange 2007 32-bit edition?

I have fielded a lot of questions lately from clients and co-workers about using Exchange 2007 in a 32-bit environment.  So, just to clarify, here are the answers to the more frequently asked questions:

1 - There is indeed a 32-bit version of Exchange Server 2007. It is *not* supported in production, however, so you should never be using this version for any real users, even if it's only a small number (or a single user for that matter).  This version was built to allow administrators and engineers a way to test and experiment with Exchange 2007 without the x64 hardware that the production version requires.

2 - You will most likely not be able to enter your license key into the 32-bit addition.  I can't find a large amount of Microsoft-official documentation on this one, but everything on the web seems to point to the evaluation version not expiring after 120 days. You will get a nag screen every time you open the Exchange 2007 GUI, but the services will still run. Please add comments if you have more definitive information on this topic, and I will post updates.

3 - It is not meant for stress testing, just for functionality testing.  This means that you can play around with the feature sets within Exchange 2007, but since your RAM will be severely limited and - very likely - your server platform will be well below what an x64 architecture will provide, you cannot expect to see those features run as fast or efficiently as they would on a "real" 2007 install.

4 - The 32-bit version is GREAT for getting your feet wet. It requires less RAM, and whatever hardware you have sitting around that will run Windows Server 2003. That means you don't have to buy a new server, just to learn how to use Exchange 2007.  Not only that, but with lower system overhead, testing/learning on Virtual Servers becomes even easier.

5 - Both the 32-bit and 64-bit editions of Exchange 2007 can communicate with 32-bit OR 64-bit Active Directory Controllers. In short, you don't have to upgrade your DC's to x64 when you put the new Exchange 2007 servers into play.

So, go out an play with Exchange 2007 on a 32-bit box if the 64-bit hardware just isn't available for your testing/learning.  Just remember, production servers absolutely must be 64-bit, otherwise if you need to call Microsoft you'll find they are less than able to assist you - which is never a good situation to be in.