Microsoft has some issues with the 64 bit version of outlook and some application that interface with it. It may be better to use the 32 bit version if available and you dont need the power of a 64 bit application
64-bit editions of Office 2010 Published: May 12, 2010
Processors that are 64-bit are becoming the standard for systems that range from servers to desktop computers. The 64-bit systems can use more virtual and physical memory than 32-bit systems. This lets users work with much larger data sets than they could previously, and to analyze and solve large computational problems. Microsoft Office 2010 introduces native 64-bit versions of Microsoft Office products to take advantage of this larger capacity. For example, this additional capacity is needed only by those Microsoft Excel users who require Excel spreadsheets that are larger than 2 gigabytes (GB). The 32-bit version of Office 2010 provides the same functionality and is also compatible with 32-bit add-ins. Therefore, the 32-bit version of Office 2010 is installed by default.
Office 2010 also provides support for 32-bit Office 2010 applications that run on 64-bit Windows operating systems by using Windows-32-on-Windows-64 (WOW64). WOW64 is the x86 emulator that enables 32-bit Windows-based applications to run seamlessly on 64-bit Windows systems. Office 2010 lets users continue to use existing Microsoft ActiveX Controls, Component Object Model (COM) add-ins, and Visual Basic for Applications (VBA), which are primarily 32-bit because no 64-bit versions are available yet for many add-ins. Supporting 32-bit Office 2010 applications that run on 64-bit operating systems allows for better compatibility with controls, add-ins, and VBA.
The recommendations for which edition of Office 2010 to install are as follows:
- <LI class=unordered>If users in your organization depend on existing extensions to Office, such as ActiveX controls, third-party add-ins, in-house solutions built on previous versions of Office, or 32-bit versions of programs that interface directly with Office, we recommend that you install 32-bit Office 2010 (the default installation) on computers that are running both 32-bit and 64-bit supported Windows operating systems.
- If some users in your organization are Excel expert users who work with Excel spreadsheets that are larger than 2 gigabytes (GB), they can install the 64-bit edition of Office 2010. In addition, if you have in-house solution developers, we recommend that those developers have access to the 64-bit edition of Office 2010 so that they can test and update your in-house solutions on the 64-bit edition of Office 2010.