This is huge, Revit Architecture users have long awaited a release of Revit that operates in the true Native format for 64 bit platforms. As many people know, 32 Bit Windows XP is limited to only 2 gigabytes of memory unless the 3gb switch is enabled. With 64 bit technology however, the machine is limited only to what the machine can physically hold which allows significantly faster computing. Prior to this release, Revit Architecture was able to installed on a 64 bit machine but never took full advantage of that platform. This release is only available to customer on Autodesk Subscription. This is a big incentive for keeping your Subscription current. Here is the exciting information about this update from Autodesk's Subscription Site.
This version of Revit® Architecture 2009 is a native 64-bit application to be used with 64-bit Operating Systems, such as Microsoft® Windows® XP Professional 64-bit or Microsoft® Windows Vista® 64-bit (Business, Home Premium, Ultimate editions). The 64-bit version of Revit Architecture 2009 removes the 4 gig memory limitation found in 32-bit applications which enhances the software’s capability to handle large projects. It contains the functionality found in the 32-bit release of Revit Architecture 2009, with the noted limitations found in the Known Issues document.