MS Office: Choosing 64 or 32 bit

Office 2010 is the first Office version to offer you a choice of either a 64 or 32 bit version. Everyone’s first reaction seems to be “gimme the 64 bit version.” This isn’t always best. It depends on how you use Office.

First, does the 64 bit version make a difference? Yes, the performance is noticeably faster. Just opening and closing the Office apps alone is faster, as well as using functions within the application. I notice it is especially fast in Outlook, which I use heavily. I have the 64 bit version on my laptop on which I do very little software development and have no need to integrate with other applications. If you can use the 64 bit version of Office, definitely go with the 64 bit.

So who should not use the 64 bit version? Anyone using an Office app that uses external references or API calls to windows. An example is an Access database that is integrated with QuickBooks (and thus has a reference to the QuickBooks library) and it has an API call to get the size of a file. In this case, the API call can still work but your developer needs to change the API call to allow for a 64 bit API call. But the QuickBooks library is 32 bit only and will never work with Access 2010 64 bit. So on development PCs in my office, I only use the 32 bit so that we can develop in Office and integrate with other 32 bit applications.

One other limitation: Some people have tried to install Access 32 bit and Outlook/Word/Excel 64 bit. That doesn’t work either. You have to install either all 64 bit or all 32 bit, but not a combination of the two. The installer won’t let you install a mixed configuration.