x64 bit hardware will run Exchange 2003 on 32 bit Windows

It seems we have some badly worded docs on some Microsoft sites that may lead you to believe that you cannot run Exchange 2003 on x64 bit systems. Also the release notes seem to be in error as well. Let me assure you that this information is incorrect and is being corrected.


You can run Exchange 2003 on x64 systems just fine. You do have to run Exchange 2003 on a 32 bit Windows version but they both run without issue on x64 systems.  


I just wanted to post this blog entry so you are not confused and think that you are locked in. If you buy an x64 bit server now you can run Exchange 2003 now and be all the more ready for a E12 64 bit version when it arrives. In fact I would recommend if you are going to buy any systems in the near future that you buy x64 systems as they will not only run Exchange 2003 now, but they will also have a slight performance improvement vs. a 32 bit system and you will be ready (hardware wise) to go to the next version of Exchange that supports 64 bit without having to buy a new system.  


Fact is your system maybe x64 bit now and you may not have notice! If you have a system that uses an Intel chip you can use this tool found at Intel’s web site that will tell you if your system is x64 bit capable http://support.intel.com/support/processors/tools/piu/sb/CS-014921.htm  if your system has an AMD chip go to the AMD site and download their tool its call AMD CPUID http://www.amd.com/us-en/Processors/ComputingSolutions/0,,30_288_809_871^9706,00.html


Or you can just check by CPU type (not always clear however) you need to have one of these procs: AMD Athlon 64, AMD Opteron, Intel Xeon with Intel EM64T support, Intel Pentium 4 with Intel EM64T.


On the related subject - if you are wondering if Exchange 2003 can run on 64-bit version of Windows, please go here.


- David Espinoza

Comments (12)
  1. lee says:

    Thanks for the clarification. I’ve seen docs saying it wasn’t allowed, as well as MS folks early on. Most recently, at Tech Ed, Dave Thomas said it could (and should) be done, but all the info was conflicting.

    Thank you for the clarification!

  2. Peter says:

    On a related note, I now hear that Exchange 12 will ONLY run on 64 bit hardware. Is that true?

  3. David Espinoza says:

    Yes Peter it is true, we will only have a 64 bit version of E12.

  4. Stefan says:

    A few weeks ago someone write here an articel about the topic that you need an DVD-reader to install E12 and gave some really funny reasons that this should be no problem in the future and now it is mentioned that you need 64 bit and no reasons are mentioned, funny…

  5. AG says:

    Bob Muglia’s Keynote address at the Microsoft IT Forum on November 15:

    We are also focusing on the next version of Exchange next year, codenamed Exchange 12. That will also be 64-bit only. The reason we have chosen to do this with Exchange is because like database, messaging is an environment that can take advantage of all of the memory that 64-bit opens up. We found that Exchange 12 has tremendously different performance characteristics than Exchange 2003 because of the incremental memory that is available to 64-bit. We found that there is a 70% reduction in the IOs required for Exchange 12. That makes us a different beast in terms of the performance characteristics. Today’s Exchange systems typically require the highest performance SAN-based systems to provide the scalability that major organisations need. With Exchange 12 and the incremental memory, the IO throughput is dramatically reduced. You may choose to continue to run it on a SAN, but the kind of IO subsystems and throughput needed will be reduced dramatically with Exchange 12. As we move forward, based on Exchange 12, our new generation solutions such as Small Business Server and Central will also be 64-bit only. We are planning on shipping those in the 2007 timeframe.

  6. Adam Gates says:

    Where E12 is made for a 64-bit platform: What happens to the old 32-bit code?

    When servers goto 128 or 256-bit what will happen to the code?

    When you write E12 do you keep in mind that 128 or 256-bit systems might be coming along before E12 has completed it’s lifecycle?

    Would it make sense to make the code in a way that is ready for the future?

  7. David Espinoza says:

    Stefan I see AG posted Bob Muglia’s Keynote address that gives you the back ground for more resons why moving to 64 bit is a good idea for Exchange stay tune we will be posting lots more on the subject. The intend of my blog was not to talk about E12 64 bit.

    Also Adam currently it is too soon to discuss any plans around 128 or 256 as both Intel or AMD have not talk about any plans yet about making any chips, so for now we are moving to 64 bit and will deal with 128 when a chip comes out. Also we do use manage code now so we think we would be ready if and when 128 bit shows up.

  8. Lubomir Hozak says:

    Nice to here, but what about the Exchange System Manager not running on WinXPx64 or Vistax64? Maybe they would be running fine if they would be avaliable in some Xadminpack.msi, but the admins must start the big setup of Exchange Server which doesn’t work on x64bit OS. :( Does anybody care about it?

  9. Joe Vivona says:

    If E12 only runs on 64-bit, what will happen to the next version of SmallBizServer. Is the 32 bit version of that dead now ? A ton of clients who run SBS, would never normally use 64 bit hardware (nor do they want to buy it). So if we’re now going to require
    SBS clients go to 64 bit, then I can’t see SBS continuing on as a product (especially since Windows 32-bit is still going to be produced, but now SBS can’t use it ??). Please explain or point me to a SBS resource that might be able to.


  10. Mike Burns says:

    I have a question about clustering.  We have Exchange 2003 on a cluster setup with server 2003 enterprise.  Our understanding the only way cluster could work right was with enterprise.  Now Exchange 12, will it work with a cluster setup somehow?  Does it require 2003 enterprise?  My research with HP says that only IA64 can support 2003 server enterprise for 64 bit.  So what is right?  Can exchange 12 run without enterprise in a cluster setup?  Or can enterprise run on a regular X64 machine?

  11. Exchange says:


    I am not 100% sure I understand your question but:

    E12 will NOT run on IA64 at all. It will run on x64. Additionally, seeing that clustering relies on MS Clustering Service, which is not present on non-Enterprise Windows, Enterprise is required for clustering to work.

    Here is more on the E12 and 64 bit story:


  12. SABARISH says:

    can u please tell me clearly… Can AMD Athlon 64-bit will run in windows xp x64-bit or x-86 ?

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