With the release of Microsoft Dynamics CRM, there is now, for the first time, both a 32-bit and 64-bit version of CRM for Outlook. This corresponds to the version of Microsoft Office 2010 that is installed on your computer–if you are running the 32-bit version of Outlook, you will need to install CRM for Outlook 32-bit, if you are running 64-bit Outlook 2010, you will need to install the 64-bit version of CRM.
So, if you have a computer running the 64-bit version of Windows 7, what version of Outlook should you run? At first glance, it appears obvious that you should install the 64-bit version of Outlook; however, there are a couple of other things to consider.
Both the 32-bit and 64-bit versions of Outlook can be installed on 64-bit Windows. The CRM Outlook client will work exactly the same with 32-bit or 64-bit Outlook. Performance will not be any faster with the 64-bit version of Outlook or CRM for Outlook. The CRM functionality will be identical.
The major consideration to be made is that when using 64-bit Outlook and the 64-bit Outlook client, web forms are launched in the 64-bit version of Internet Explorer.
64-bit IE does not support many of the add-one supported by the 32-bit version of IE, such as Silverlight. If you are running the 64-bit version of Outlook, you may potentially limit the level of custom enhancements and add-ons you may be able to access via CRM for Outlook.
This is the main reason we recommend that for now, even if you have 64 bit Windows, you continue to use the 32-bit version of Microsoft Office 2010 (or Office 2007, which is 32 bit). I can speak from personal experience that the 32-bit version of Outlook 2010 works great on a computer with 64-bit Windows.